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Obelisks in Ancient Egypt

BRIAN A. CURRAN

Among the characteristic monumental forms employedby the Egyptians – pyramids, sphinxes, etc. – theobelisk seems to have enjoyed the richest and mostdistinctive “afterlife.” Over the two millennia of theiroriginal production, Egyptian obelisks varied in sizefrom relatively small funerary stones to the slender,towering monoliths of red Aswan granite that wereerected before and within the precincts of the greatestEgyptian temples. Obelisks were dedicated in mostcases to the solar gods of Egypt, and their soaringheight and tapering shape – capped by a pyramidal(and originally gilded) pinnacle called a pyramidion,seemed to reach from the earth into the heavens andtouch the rays of the life-giving sun. For centuries tocome, these great stones have challenged the imagina-tions of spectators: Greek and Roman, Christian andMuslim, Renaissance and Modern –who were awed bytheir soaring height, titanic weight, and paradoxicallyslender and tapering shape. They were endowed withan aura of sanctity and power through their associationwith the gods and rulers of a civilization that wasalready viewed as almost unimaginably ancient by theGreeks and Romans. This aura was embodied for manyby the hieroglyphic carvings that covered their fourfaces, which were believed from Classical times to theage of Napoleon To encode, in veils of allegory andenigma, the most secret doctrines of Egyptian religionand science (Iversen 1961; Curran 1998/1999, 2003).

In the classic formula of the New Kingdom, bestrepresented until the 1830s at the Temple of Amun-Rain Luxor, a pair of obelisks was erected before thesanctuary’s main entrance pylon. These pylons wereconceived as sacred “horizons” that marked the passagefrom the realm of mortals to the kingdom of the gods.In this context, the obelisks literally rose to “pierce”the sky and commune with the deities of the risingand setting sun, just as the ceiling of the temples’colonnaded halls supported ceilings carved with thestars and constellations of the heavens (see Bell 1997:133–134). But the biggest obelisk ever erected – the

32.15 m (105.5 foot), 455–510 ton obelisk ofThutmose III (1479–1424 BCE) was set up as a singlemonument at the Great Temple of Amun-Ra in Karnak.This towering monolith of red granite was quarried –like all the major Egyptian obelisks – at Aswan inUpper Egypt. Still incomplete at Thutmose III’s death,the obelisk was completed (with additional inscrip-tions) and erected some 35 years later by the King’sgrandson, Thutmose IV (1400–1390 BCE). For nearlytwo millennia the great obelisk stood alone as an objectof special veneration at Karnak, until it was torn fromits base by order of the emperor Constantine (306–337BCE) and, after a series of delays, transported to Romeby his successor, Constantius II (337–361 BCE), in 357BCE. Upon arrival, it was raised on the spina or medianstrip of the Circus Maximus; next to a very large (butsmaller) obelisk erected more than three centuriesearlier by Augustus (see below). In 1587–1588, theobelisk was located and excavated from the ruins ofthe Circus by order of Pope Sixtus V, who initiated thesecond great phase of obelisk installations in Rome.The obelisk was moved to the Piazza of San Giovanniin Laterano and its broken pieces were set in place by agreat “obelisk machine” devised by Domenico Fontana(for its present location, see Fig. 1). In 2006, the obeliskwas again surrounded by scaffolding, erected topreserve and restore the monument from the ravagesof traffic, pollution, and a terrorist bomb (for the fullhistory of the Lateran obelisk; see Iversen 1968–1972,1:55–64; Habachi 1984: 112–117; D'Onofrio 1992:243–259).

HistoryAs the story of this largest of all Egyptian obelisks amplyillustrates, these monuments attracted the enviousand acquisitive eyes of self-styled successors of thePharaohs from the time of the Ptolemies and Romanemperors to relatively modern times. As a consequence,a large number of them have been yanked from theiroriginal locations in Egypt and transported at greatexpense (and with great fanfare) to provide ornamentsfor the capital cities of the Roman and later empires.Rome received the bulk of them, to the extent thatsome 48 of themwere visible in the city by themiddle ofthe fourth century BCE. Thirteen of these can be seen in

Obelisks in Ancient Egypt. Fig. 2 Alexandria/Central Parkobelisk of Thutmuse III, New York City.

Obelisks in Ancient Egypt. Fig. 1 Lateran obelisk ofThutmose III and IV, Rome.

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the city today, thanks to the efforts of generations ofpopes and other patrons who sought to associatethemselves with the majesty of the pharaohs andemperors who originally made or appropriated them.Still others may be admired in Istanbul, Paris, London,and New York (Fig. 2), where they testify to theenduring attraction of the obelisk’s pharaonic andimperial legacy. In addition to their symbolic power,the obelisks also posed, at virtually all stages of theirhistory, a daunting challenge to the skill and ingenuityof the engineers and builders who sought to move andre-erect them. In a very real sense the story of the obelisksmay be understood, at least partially, as a history inmicrocosm of engineering and transportation technologyin the Mediterranean world (on this point see Engelbach1921, 1922; Fontana 1987; Parsons 1939: 155–173;Dibner 1950; Carugo 1978).

The modern name obelisk derives from the Greekobeliskos, a diminutive that means “little spit.” It is fromthis perhaps deliberately ironic term that the Romansderived the Latin obeliscus. Among the AncientEgyptians, these monuments were called tekhen –plural tekhenu – which derives from a verb meaningpierce (Iversen 2006, “Obelisk,” Grove Art website).The precise meaning of their distinctive shape is alsouncertain, although the Roman author Pliny the Elder’sreport that “an obelisk is a symbolic representation of thesun’s rays, and this is the meaning of the Egyptian word

for it” may have much to recommend it (Pliny, NH36.14.64). Most scholars associate the obelisk’s originwith the ancient solar cult at Heliopolis, and it seems likethat its prototype was a much older type of stonemonument known as the ben or benben. These culticstones, which apparently took a pyramidal form, werededicated to the sun gods Atum and Re or Re-Harakhtiin the sanctuary at Heliopolis. The Egyptians believedthat thebenben originated at the beginning of time,whenit provided the seat for the Atum’s creation of theuniverse. The benben was also associated with thesacred phoenix or Benu-bird, whose cycle of self-creation and resurrectionwas associatedwith the cults ofthe dead and the rising and setting of the sun (Iversen1968–1972, 1:11–15; Habachi 1984: 3–6).

Both archaeological and inscriptional evidence makeit clear that obelisks of various types were being erectedby the rulers of Egypt during the later dynasties ofthe Old Kingdom (2686–2160 BCE). Among these,perhaps the most notable were a pair of obeliskstransported on large ships from southern Egypt toHeliopolis by the sixth Dynasty Pharaoh Pepi II (2278–2184 BCE – Habachi 1984: 40–41). During thepreceding fifth Dynasty (2494–2345 BCE) a seriesof solar temples with obelisk-like centerpieces wereerected near the pharaonic cemetery at Abu Sir. These“obelisks” were fashioned not from single blocks ofstone, but from masonry blocks and sheathed with fine

Obelisks in Ancient Egypt. Fig. 3 Obelisk of Thutmose I,Karnak.

Obelisks in Ancient Egypt. Fig. 4 Obelisk of Hatshepsut,Karnak.

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white limestone in the manner of the pyramid tombs ofthe time. During the same period, diminutive obelisk-shaped stones began to be erected in pairs at theentrances to tombs. These were generally installedfacing east, presumably to present themselves to the raysof the rising sun, which represented the resurrection ofthe deceased in Egyptian belief. These early funeraryobelisks were usually fashioned from limestone andwere inscribed on one sidewith the name of the deceased(Kuentz 1932; Habachi 1984: 41–46).

The earliest surviving large-scale, monolithic obeliskwas erected by the 12th Dynasty Pharaoh Senusret I(1985–1956 BCE) in the sacred city of Heliopolis onthe occasion of his jubilee year. This was originally oneof a pair that was carved from the durable mottled-redgranite (or Syenite) from Aswan in Upper Egypt, wherelater obelisks of this size were also quarried. They wereshipped up the Nile and erected before a new or rebuilttemple dedicated to the sun god Re-Harakhti. TheHeliopolis obelisk, like all succeeding obelisks of the“classical” type, is a four-sided monolith, carved from asingle piece of Aswan granite. It stands some 67 ft(20.4 m) high on a squared base and weighs some120 tons (Habachi 1984: 46–50).

Since no other obelisks datable to the MiddleKingdom have survived, the true successors ofSenwosret’s monuments are the ones produced by theNew Kingdom rulers of the 18th and 19th Dynasties(1550–1186 BCE). This great series of obelisks beginswith a pair dedicated to Amun-Ra at Karnak by the18th Dynasty pharaoh Thutmose I (1504–1492 BCE).One of these, which rises nearly 66 ft (20,016 m) highand weighs an estimated 143 tons, still stands on itsoriginal pedestal in the temple precinct (Fig. 3), whilethe other survives only in fragments. Thutmose I wassucceeded after the short reign of his son (Thutmose II)by that king’s “royal wife” (and half-sister) Hatshepsut(1473–1458 BCE). Hatshepsut erected no less thanfour large obelisks at Karnak, in two pairs. Of these,only one still stands intact today (Fig. 4). This greatobelisk, which rises to a height 96.78 ft/29.5 m andweighs some 323 tons, is one of the pair set up here onthe occasion of her Jubilee. The lower part of itscompanion stands nearby on its original base, and somefragments can also be seen on site and in variousmuseums. Of the second pair that Hatshepsut erected atthe beginning of her reign in the eastern section of thetemple, only fragments survive today. But a visualrecord of their transport is preserved in the reliefdecoration in the Queen’s funerary temple at Deir el-Bahari. Here, the obelisks are shown loaded end to endon a large ship pulled by three rows of boats for theirjourney “down” the Nile from Aswan to Thebes(Habachi 1984: 56–72).

Hatshepsut’s successor Thutmose III (1479–1425)was responsible for the production of at least nine

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obelisks, including seven erected at Karnak and two atHeliopolis. Of these, only the Lateran colossus (seeabove), the Heliopolitan pair – which were transferredto Alexandria in Augustan times and are now inLondon and New York City (for the latter, see Fig. 2)and the Hippodrome obelisk in Istanbul – which stoodbefore the seventh pylon at Karnak until it wasremoved by Constantine and raised in Constantinopleby the Emperor Theodosius (379–395 BCE) – survivetoday (Habachi 1984: 72–77). During the 19th orRamesside Dynasty, the Pharaohs Sety I (1294–1279BCE) and Rameses II (1279–1213 BCE) erectedobelisks in a number of locations, including Luxor,Heliopolis, and Piramesse. One celebrated survivor isthe so-called Flaminian obelisk (ca. 75 ft/22.84 m,263 tons), which was quarried by order of Sety I andcompleted and erected in Heliopolis by Rameses II. Itwas transported to Rome and set up in the CircusMaximus by Augustus, and re-erected in the Piazza delPopolo by Pope Sixtus V in the late sixteenth century(Fig. 5, and see more below).

During later dynasties obelisks continued to bemade, sometimes out of different types of stone and insome cases on a smaller scale. The largest survivingspecimen from the later periods is the so-calledMontecitorio obelisk (21.79 m, 230 tons in its present,reconstructed form), which was one of a pair raised by

Obelisks in Ancient Egypt. Fig. 5 Flaminian obelisk ofSety I and Rameses II, Piazza del Popolo, Rome.

the 26th Dynasty pharaoh Psamtek II (664–610 BCE)at Heliopolis and also later taken to Rome (see Fig. 6).The last surviving obelisks commissioned by a nativeEgyptian pharaoh were a much small pair carved fromhard black schist for Nectanebo II (360–343 BCE) ofthe 30th Dynasty. They were dedicated to the Egyptiangod Thoth and presumably set up at that god’s templein the city of Hermopolis. At the end of the Napoleoniccampaign in Egypt, two fragments of these obeliskswere turned over to British forces by the Frenchand sent to the British Museum, where they may beseen today. A third fragment is in Cairo (Iversen1968–1972, 2:51–61; Habachi 1984: 101–103).

During the rule of the Macedonian PtolemaicDynasty (332–30 BCE), temples and monumentscontinued to be produced in the traditional Egyptianmode. Among the embellishments for these was thepair of smallish obelisks erected at the Temple ofIsis in Philae by Ptolemy IX (107–80 BCE). One ofthese obelisks (22 ft/6.7 m tall, 6 ton) was discoveredin 1815 by the British nobleman and scholar WilliamJohn Bankes (1786–1855). In 1819 Bankes discoveredthe lower part of its mate and hired the famousItalian strongman turned explorer–excavator, GiovanniBelzoni, to help remove the obelisks and their bases(inscribed in Greek) to his Kingston Lacy estate inDorset, England. In 1839, Bankes erected the intact

Obelisks in Ancient Egypt. Fig. 6 Solarium obelisk ofPsamtek II, Piazza di Montecitorio, Rome.

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obelisk on its pedestal in the garden of the estate. Itshieroglyphic inscriptions and the Greek ones on itsbase were among the key documents in the decipher-ment of the Egyptian hieroglyphic script by Egyptolo-gist Jean-François Champollion (1790–1832) in1822 (Iversen 1968–1972, 2:62–85; Habachi 1984:105–108).

Obelisks in Ancient Egypt. Fig. 7 Unfinished obelisk,Aswan.

Obelisks in Ancient Egypt. Fig. 8 Trench of unfinishedobelisk, Aswan.

Obelisks in Ancient Egypt. Fig. 9 Dolerite hand-tool,Aswan.

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Manufacture and InstallationThe methods the Egyptians used for the manufacture,transport, and erection of obelisks are not fullyunderstood (for what follows, see Engelbach 1922,1923; Habachi 1984: 15–37; Arnold 1991: 36–40,47–52, 57–73). Most of the evidence we have comesfrom the study of extant monuments, investigation intoEgyptian building and stone-cutting techniques, and afew visual representations that survive from pharaonictimes. But the richest source of information has comefrom the archaeological study of a large unfinishedobelisk, believed to be of Thutmosid (New Kingdom)date, that still lies in one of the granite quarries atAswan (Fig. 7). This obelisk, which was originallylaid out at a height of 41.75 m (ca. 137 ft), wouldhave weighed about 1,168 tons if extracted. It wasabandoned– after an attempt to reduce its length–whenit developed irreparable cracks in its upper section.Excavation of the monument by Engelbach in 1921–1922 revealed that the ancient workmen began bycutting test shafts into the rock. Then, after laying outthe obelisk’s shape on the surface, they began removingthe upper layer of uneven stone to expose a suitablepiece for excavation. Then came the arduous task ofdigging trenches on all four sides to provide work areasfor the quarrymen to form and separate the block (seeFig. 8). From the evidence of surface marks and toolsfound on the site, it seems clear that this work was donewith ball-shaped tools of ultra-hard dolerite stone(Fig. 9). When the trenches reached the required depth,the workers had to undercut the shaft to extract theobelisk from the bedrock. Then the obelisk had to bepulled or lifted from the quarry bed, smoothed andpolished on site (in at least one case, parts of thehieroglyphic inscription were added at this phase) andprepared for transport. At all stages of work, includingthe carving of hieroglyphic inscriptions, the work wasdone with stone tools and abrasives like emery, sincethe copper and bronze tools of the time were not strongenough to cut the hard granite.

Visitors to the site may be surprised to discover thatthe unfinished obelisk was carved at a considerableangle longwise, with the pyramidion at the highestpoint on the east side and the bottom much lower on thewest. By removing the deposit of granite at the opposite(bottom) end, it seems that the workers could have pulledthe great stone out of the quarry with the help of its own

Obelisks in Ancient Egypt. Fig. 10 Vatican obelisk, Rome.

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massive weight. But Engelbach has argued that thefailure to remove the rock from the west end, coupledwith the removal of stone from the area of the pyramidionon the east side, suggests that the workers planned to liftthe obelisk from the bed with the help of large woodenlevers and remove it from the front end of the trench(Engelbach 1923: 41–51).

Once the obelisk had been removed, the workmenloaded it onto a large sledge, which was pulled by ateam of laborers on a track or ramp to the riverbank fortransfer to a specially constructed transport ship. Uponarrival, it was rolled off and dragged in the samemanner to the site where it was to be erected. At thisstage, the builders faced the difficult (and potentiallydangerous) task of raising the monument to an uprightposition on its pedestal block. Direct evidence for howthis was done does not survive, but a number ofplausible hypotheses have been put forward. We knowthat Egyptian builders used three main methods forraising large stones – levering, pulling with ropes, ordrawing them up a ramp-like incline. It was the opinionof Engelbach that the workers dragged the monumentbottom-end first up a ramp-like incline to a point someheight above the base, after which it was pulled uprightby ropes and lowered onto the pedestal, where it waspositioned by levers and the gradual removal of sand. Aversion of this method was represented in suitablydramatic terms in the 1956 film, The Ten Command-ments . A series of attempts to duplicate this methodwith a modern obelisk finally succeeded in 1999 (seeHandshouse Projects 1999; Nova Online: Mysteries ofthe Nile, http://www.pbs.org/wgbh/nova/egypt/raising/).

Rome and the First Afterlife of the ObelisksObelisks continued to be erected, moved, and in a fewcases, manufactured anew during the Roman era,which followed the defeat of Cleopatra VII (51–30BCE) and her ally Marc Anthony by Octavian, whobecame known as the Emperor Augustus in 28–27BCE. Egypt became a province of the Roman Empire,and the granite quarries at Aswan came under Romancontrol, providing a rich supply of monolithic columnsand other products for the great building projects ofRome and its empire. The first prefect of Egypt underAugustus, Cornelius Gallus (30–26 BCE), was respon-sible for laying out a new forum complex, called theForum Julium, at a site near the Ptolemaic capital ofAlexandria. As an ornament to this space, Gallusordered the erection of the so-called Vatican obelisk –the big, 331 ton, 83 ft (25.31 m) colossus that nowstands in the Piazza di San Pietro in Rome (Fig. 10).Since it lacks a hieroglyphic inscription, is not knownwhen or by whom this most celebrated of obelisks wasoriginally quarried. Pliny the Elder reports that it hadbeen originally raised in Egypt by the pharaoh

“Nencoreus, the son of Sesostris,” but it has beenpersuasively argued (Alföldy 1990) that it was original-ly quarried by Cleopatra VII as a monument to JuliusCaesar and appropriated by Gallus, who added aninscription in bronze letters to the lower-end of the shaftthat essentially dedicated the obelisk to himself. Theletters were removed after Gallus was forced out ofoffice on charges of corruption and took his own life toavoid prosecution (the fastening holes for the inscriptionwere discovered during analysis of the obelisk’s surfacein1959). Sometime after this, presumably during thereign of emperor Tiberius (14–37 BCE), a secondinscription, now eroded but still visible, was carved onthe lower east and west faces of the monument (Fig. 11)which rededicated the monument to Augustus, “son ofthe divine Julius,” and to Tiberius himself (for theVatican obelisk, see Iversen 1968–1972, 1:19–21;D'Onofrio 1992: 97–185; Alföldy 1990).

In 13–12 BCE, Augustus ordered a pair of obelisksoriginally raised by Thutmose III (with later inscrip-tions of Rameses II) in Heliopolis to be transferred toAlexandria, where they were set up – facing the sea –before the so-called Caesareum, a complex dedicated tothe cult of Julius Caesar. These had apparently beenbegun as a mausoleum for Marc Antony toward the endof Cleopatra VII’s reign. The obelisks were set on theirbases with their corners bronze, crab-shaped astragals –one of which, now in the Metropolitan Museum in

Obelisks in Ancient Egypt. Fig. 11 Latin Inscription,Vatican obelisk, Rome.

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New York – was inscribed in both Greek and Latin tocommemorate its dedication by Publius RubiusBarbarus, prefect of Egypt. In the later nineteenthcentury, these obelisks, one of which had fallen butremained intact, were presented as “gifts” from theEgyptian authorities to the British and Americangovernments and transported to London and New YorkCity (Fig. 2), respectively (Gorringe 1882; Iversen1968–1972, 2:90–147; Habachi 1984: 165–182;D'Alton 1993).

In 10 BCE, 20 years after the defeat of Antony andCleopatra, Augustus ordered the transport of two largeobelisks from Heliopolis. By this time, according tocontemporary reports, this great Egyptian city hadfallen on bad times, and its marvelous temple had falleninto disrepair. The first, originally carved by order ofRameses II and his father Sety I (and now in the Piazzadel Popolo, Fig. 5), was erected on the spina of theCircus Maximus (see Iversen 1968–1972, 1:64–75;D'Onofrio 1992: 260–266). The second, the aforemen-tioned obelisk of Psammetichus II (now in the Piazza diMontecitorio, see Fig. 6), became the gnomon of agigantic sundial in the Campus Martius (Iversen 1968–1972, 1:142–160; D'Onofrio 1992: 369–421). Bothwere capped by gilt-bronze spheres with obelisk-shaped pointers and provided with identical inscrip-tions on their red granite bases:

IMP. CAESAR. DIVI. FIL. AVGVSTVS. PON-TIFEX. MAXIMUS. IMP. XII. COS. XI. TRIB.POT. XIV. AEGVPTO. IN. POTESTAM. POPV-LI ROMANI. REDACTA. SOLI. DONVM.DEDIT.

When Imperator for the twelfth, consul forthe eleventh, and tribune of the people for thefourteenth time, Imperator Augustus, son of thedivine Caesar, dedicated this obelisk to the sunwhen Egypt had been brought under the sway ofthe Roman People (Iversen 1968–1972, 1:65, 142).

As the inscription makes clear, Augustus’ obeliskswere intended to commemorate his conquest of Egypt.In both cases, the new installations corresponded to theoriginal Egyptian dedication of these monuments tothe sun, but gave this theme a new and distinctly Romanspin. In the case of the Circus Maximus, which wastraditionally associated with the solar cult, the obelisktook it its place on the spina or median strip as anembodiment of the sun’s power, while the chariots thatraced around it came to be considered symbols of theplanets moving around it. In the Campus Martius, thePsamtek obelisk was put to use as a solar instrument, asdescribed by Pliny the Elder (1938–1963): (NaturalHistory, Ed. Rackham and Eichholz, 10:55–57).

The one in the Campus Martius was put to use in aremarkable way by Augustus of Revered Memoryso as to mark the sun’s shadow and thereby thelengths of days and nights. A pavement was laiddown for a distance appropriate to the height ofthe obelisk so that the shadow cast at noon on theshortest day of the year might exactly coincidewith it. Bronze rods let into the pavement weremeant to measure the shadow day by day as itgradually became shorter and then lengthenedagain. This device deserves to be carefullystudied, and was contrived by the mathematicianNovius Facundus. He placed on the pinnacle a giltball, at the top of which the shadow would beconcentrated, for otherwise the shadow cast bythe tip of the obelisk would have lacked definition(Pliny, NH 36.14.69–72).

It is unclear from Pliny’s description whether thisdevice was designed as a solarium (which measuredthe daily length of the sun’s shadow on a meridian) ora horologium (a more elaborate device capable ofmeasuring the length of the hours of the day), but hisadmiration for the device was undiminished by hisobservation that “the readings thus given have for aboutthirty years past failed to correspond to the calendar.”During the fifteenth and sixteenth centuries, pavementswith “lines of gilt metal” and mosaics representing thewinds were thought to be remains of the devicedescribed by Pliny (Iversen 1968–1972, 1:144–149).In 1979–1981, a section of travertine pavement, with ameridian strip with Greek inscriptions in bronze letters(denoting signs of the zodiac and the Etesian winds),was discovered in the area immediately north of theobelisk, confirming the basic veracity of Pliny’saccount, although problems of interpretation andfunction remain (Buchner 1982; Schütz-Tübingen1990). As for the obelisk itself, it was still standing inthe eighth century but was thrown down and broken atsome later date and discovered (and reburied) in about1512. It was finally excavated in 1748, and after severalabortive attempts, repaired (with fragments of a large

Obelisks in Ancient Egypt. Fig. 12 San Macuto obelisk ofRameses II, Piazza della Rotunda, Rome.

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granite column) and re-erected in the Piazza diMontecitorio in 1789 by order of Pope Pius VI. It wasintended to lay a modern meridian to track the obelisk’sshadow at this time, but the idea was not realizeduntil 1998, when the pavement was restored to designsby the architect Franco Zagari (see Zagari, http://www.franco zagari.it/H OM E /Pi azza%20Montecitorio/montecitorio.htm).

But impressive as these installations undoubtedlywere, it was the feat of transporting them across theMediterranean to Rome that impressed Roman com-mentators on the subject. Pliny reports that the ship thatwas specially constructed to carry Augustus’ obelisksto Rome was considered such a wonder in its own rightthat it was placed on display in a “permanent dock” atPuteolis (modern Pozzuoli) to commemorate theachievement – although it was later destroyed by fire.He adds that the ship used by Gaius (Caligula) to movethe third (Vatican) obelisk to Rome was likewisepreserved until it was filled with concrete and sunk aspart of the Claudian harbor-works at Ostia. Excavationsin 1957–1960 near Rome’s Fiumicino airport nearRome Ostia in 1957–1960 uncovered the concrete coreof the Vatican obelisk ship, which preserved a partial“impression” of the vessel that once had borne it. Froma reexamination of this and other evidence fromEgyptian and Roman sources, Wirsching (2000) hasproposed reconstructions of both Egyptian and Romanobelisk and column-carrying ships – and has concludedthat both riverine and seagoing vessels used a ballasteddouble hull to control the level of the ship for loadingand unloading the monoliths.

When it came time to transport and raise the obeliskson land, the Romans were able to use a variety oftechniques that had not been available to the Egyptians,including iron tools and heavy lifting cranes Employ-ing ropes and pulleys. The most extensive descriptionof the Roman procedure is provided by the fourthcentury historian AmmianusMarcellinus, in his accountof the transport and erection of the Lateran obelisk(Fig. 1) in the Circus Maximus under Constantius II in359. He reports that upon its arrival in Italy, the obeliskwas put on a chamulcus (a kind of sled or cradle) and“carefully drawn” through the Ostian gate to the CircusMaximus,where itwas raised using a device resemblinga“veritable grove” of beams and derricks and powered byan army of men turning wheels “that resembled mill-stones” (Ammianus, 17.4.14–15; Ammianus, Rolfe1950–1952, 1:325–327). The great stone was graduallyraised and lowered on its base on the spina of the circus,where it joined (and to a certain extent upstaged)the obelisk erected by Augustus over three and a halfcenturies earlier. Ammianus’ description of the Roman“obelisk-raising” machine corresponds in generalterms to the equipment depicted on the base of theHippodrome obelisk in Constantinople, erected by

Theodosius I, 379–395 (Bruns and Krauss 1935:47–53; Iversen 1968–1972, 2:15–16; Killerich 1998:69–72). It is also the same basic method that wassuccessfully employed by Domenico Fontana to movethe Vatican obelisk in 1586 (see below).

As the story above illustrates, later Roman emperorsemulated Augustus’ taste for transporting obelisks. Thenext to be moved to Rome after Augustus (that weknow of) was the one in the Forum Julium atAlexandria, which was shipped to Rome and raisedon the spina of the Vatican Circus by order of GaiusCaligula (37–41 BCE, see more below). These werefollowed by some 45 others in the three and a halfcenturies that followed. Among them were at least sixsmall obelisks of 19th and 26th Dynasty vintage thatwere installed (at an unknown date) in the Romansanctuary of Isis in the Campus Martius: the IseumCampense (Iversen 1968–1972, 1:93–114, 174–177;Roullet 1972: 35, 72–77-cat nos. 73–80; Lembke1994: 202–210-cat nos. 48–53). These include theobelisk now in the Piazza della Rotunda in front of thePantheon (Fig. 12), which was originally raised inHeliopolis by Rameses II and set up at the beginning ofthe fifteenth century in the nearby Piazza di SanMacuto (which marked the northernmost section of theIsis sanctuary). Its fragmentary counterpart, now in thegardens of the Villa Celimontana in Rome (Fig. 13),had been restored and set up even earlier, during the

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twelfth to thirteenth centuries, on the Capitoline Hill.Other obelisks from the Iseum, discovered in thesixteenth to nineteenth centuries, can be seen in otherlocations in Rome, Florence, and Urbino. The lastobelisk to be transported out of Egypt by a Romanemperor was raised in the Hippodrome of Constanti-nople by Theodosius I in 390 BCE. Originally one of apair set up at Karnak by Thutmose III, this 30 m, nearly400-ton colossus (it apparently broke during transportand now stands some 19.5 m–65 ft) was one of at leastfive obelisks that once stood in the city. Most of thesehave disappeared without a trace.

In addition to importing obelisks from Egypt, theRomans also produced their own new obelisks whenthe circumstances required it. Two that may have beenproduced directly for Roman use are the pair ofuninscribed obelisks that were placed before themausoleum of Augustus in Rome. They were erectedat an unknown date (probably the first century BCE)and fell into the debris of the city sometime during themiddle ages. In the sixteenth century, one of them wasexcavated and after years of neglect, was erected byPope Sixtus V on the Esquiline Hill. In the eighteenthcentury, the second was discovered and installed inthe Piazza del Quirinale by Pope Pius VI (Iversen1968–1972: 47–54, 115–127).

A more certain case of Roman manufacture is the so-called Pamphilian obelisk, which was inscribed with

Obelisks in Ancient Egypt. Fig. 13 Capitoline Obelisk ofRameses II, Villa Celimontana, Rome.

vignettes and hieroglyphic inscriptions of the emperorDomitian (81–96) in honor of the Egyptian gods.During the fifteenth and sixteenth centuries, thismedium-sized and exceptionally slender obelisk(16.54-m tall) lay broken in the ruins of the Circus ofMaxentius on the Via Appia outside the walls of Rome.It remained there until the middle of the seventeenthcentury, when it was repaired and erected as thecenterpiece of Bernini’s Fountain of the Four Rivers inthe Piazza Navona (Fig. 14). It has been proposed thatthe Pamphilius was originally raised in the centralentrance-court of the Iseum Campense when it wasrebuilt by Domitian after a fire in 80 BCE, but this is byno means certain. The inscriptions mention Isis andallude to the emperor’s restoration of “that which hadbeen destroyed,” but the principal dedication is to thesun god Re-Harakhte. It is possible that it was made foranother Roman site, or even – as seems to be the casewith the obelisk of Antinous (see below) – fordedication in an Egyptian setting, and only later foundits way to Rome.During the reign of Hadrian (117–138), a smaller

obelisk was carved in honor of the emperor’s latecompanion Antinous, who drowned in the Nile duringan Imperial visit to Egypt and was deified as a kind ofmodern Osiris in Egypt and elsewhere in the Empire.This obelisk was originally manufactured and, accord-ing to most recent theories, probably set up in Egypt

Obelisks in Ancient Egypt. Fig. 14 Pamphilian obelisk ofDomitian, Fountain of the Four Rivers, Rome.

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Obelisks in Ancient Egypt. Fig. 15 Obelisk of Hadrian andAntinous, Monte Pincio, Rome.

1782 Obelisks in ancient Egypt

near the site of the unfortunate boy’s tomb. But it waseventually brought to Rome and erected in the thirdcentury in the Circus Varianus near the Via Labicana,where two fragments of its broken shaft were visible inthe fifteenth and sixteenth centuries. These pieces wereexcavated and partially re-erected by the Saccociusbrothers, who owned the property, in 1570. Then, aftera period of neglect, the obelisk was purchased byCardinal Francesco Barberini in 1632, and after somefurther peregrinations, was installed in Rome’s Pinciangardens by Pope Pius VII in the early nineteenthcentury (Fig. 15).

Obelisks from the Middle Ages to Modern TimesDuring the middle ages, the obelisks continued toattract their share of interest from learned observers,even while many of them were toppled and otherwiseneglected or vandalized in Egypt and Rome. They alsoacquired new names that continued to emphasize theirneedle-like shape. The common Medieval (and mod-ern) Arabic word for an obelisk is mislah or missala,which refers to a “patching needle” and thus, likethe Greek obeliscos, emphasizes the slender, needle-like shape of these monuments. During the middleages, the obelisks of Senusret at Heliopolis (alongwith the Alexandrian pair) were popularly knownas Messalat Far'un (Needles of Pharaoh). Arabic scho-lars called the hieroglyphic carvings on the obelisks

and other Pharaonic monuments by a variety ofnames, including “bird’s script” (qalam al-tayr),“temple-script” (al-qalam al-birbawi), and “hieratic”script (al-qalam al-kahini) (Habachi 1984: 3–5, 48;Haarmann 1996; El Daly 2003).

In Egypt, then, it is clear that the obelisks, like thepyramids and other monuments, retained their Phara-onic associations into the Medieval period. But thesituation was more complicated for the “obelisks inexile” in Rome. It is true that thanks to the writings ofscholars like Isidore of Seville the Egyptian origins andtraditional name of obeliscus was never entirelyforgotten in the Latin west (Isidore of Seville,Etymologiae 18.28–31). But in the ancient capitalitself, as the obelisks fell victim to the indignities ofneglect, earthquake, and vandalism, thememory of theirEgyptian origins also began to fade, and was super-seded by new or alternate associations with Romanhistory and legend. By the middle of the twelfthcentury, the only obelisk of great size that was stillstanding in Rome was the Vaticanus (Fig. 10 ), whichby this time was believed to mark the site of the ApostlePeter’s martyrdom in the Vatican circus. According to asecond tradition set out in the Mirabilia urbis Romae,an influential twelfth century guide to the antiquities ofRome, the obelisk had originally been raised as themonument and tomb of Julius Caesar, whose asheswere believed to be interred in the bronze globe at themonument’s summit. Although other texts of the timereferred to this and other monuments in Rome aspyramids or obelisks, the preferred name for theVatican monument, and later, for other Romanobelisks, was the guglia or “needle” of Caesar (variantsof the term include agulia and aguglia). Derived in partfrom a misreading of a passage in Suetonius’ Life ofCaesar and the Latin inscription on the monuments’shaft, the association with the “Divine Julius” and thename guglia persisted in common parlance long afterboth the true origin and function of the monument hadbeen established by Renaissance admirers (Iversen1968–1972, 1:22–28; Curran and Grafton 1995).

By the middle of the fifteenth century, Italianhumanists had identified the obelisks in Rome as theEgyptian monuments “in exile” described by Pliny andAmmianus, and had already embarked on the earlieststages of a long and complicated effort to understand anddecipher their hieroglyphic inscriptions. In the early1450s, builders working for the “humanist” PopeNicholas V (1447–1455) conducted the first archaeo-logical investigation of the Vatican obelisk in relation tothe Pope’s plan tomove the great stone from the remainsof the circus on the south side of St Peter’s basilica to thepiazza in front of it – a distance of some 275 yards.Accounts of the papal architects’ claims to have devisedmachines capable of lifting and moving the great stonespread as far as the northern court of Ferrara, and

Obelisks in ancient Egypt 1783

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inspired a host of imaginative obelisk projects –most ofthem quite impossible to realize, on the part ofRenaissance artists and architects (Curran and Grafton1995: 242–244). But this and other plans to move theobelisk or erect other ones that were discovered in theruins of Rome were delayed for many years, until 1586,when the transport of the Vatican obelisk was achieved,with great fanfare, by Pope Sixtus V (1585–1590) andhis architect-in-charge, Domenico Fontana (1543–1607). To achieve this long-postponed goal, Fontanadevised a great obelisk-lifting and lowering machine –called a castello – that resembled a wooden siege-towerabout 92 ft tall – just tall enough to life the obelisk fromits base and lower it to a horizontal position, using asystem or ropes and pulleys powered by capstans turnedby teams of some 900 men and 74 horses. The obeliskwas then transported to the piazza on a speciallyconstructed causeway and raised on its original (albeitrestored and elevated) base by reversing the loweringprocess. The obelisk was solemnly rededicated to theHoly Cross and ceremonially exorcized of all pagan,demonic forces, and Fontana himself was lauded as thehero of the moment and showered with titles and giftsappropriate to his achievement. During the next 3 years,Fontana used his obelisk-lifting machine to raise andrepair the broken fragments of three more obelisks – thetwo large ones excavated from the Circus Maximus(which he raised in the Lateran and the Piazza delPopolo, respectively) and a smaller specimen that hadbeen discovered decades earlier in the ruins of theMausoleum of Augustus, which was set up on theEsquiline hill, near the apse of the Basilica of SantaMaria Maggiore (for Fontana’s account and laterstudies, see Fontana 1978; Parsons 1968: 155–173;Dibner 1970: 21–43; Iversen 1968–1972, 1:29–40;D'Onofrio 1992: 71–92).

During the later seventeenth and eighteenth centu-ries, a series of smaller and/or broken obelisks wererepaired and re-erected in Rome, including the Obeliskof Domitian (Fig. 14), which was restored under thesupervision of the Jesuit polymath Athanasius Kircher(1601/1602–1680) and installed as the centerpiece forBernini’s richly allegorical Fountain of Four Rivers in1649 (see Iversen 1968–1972, 1:76–92; Preimesberger1974; Rowland 2001; Parker 2003); and the recon-structed fragments of the Campus Martius sundialobelisk, which was repaired with red granite from thedamaged column of Antoninus Pius and set up in thePiazza di Montecitorio by order of Pope Pius VI in1786 (Fig. 6). It was one of three obelisks re-erected bythis pope, whose projects represented the final chapterin grandiose papal appropriation of these monuments(see Collins 2001, 2004). During the nineteenthcentury, would be European and American obelisk-importers shifted their gaze from Rome to Egypt itself,as the monuments of the country attracted new

enthusiasm following the Napoleonic campaign of1798–1801 and the subsequent decipherment of thehieroglyphic script by Jean François Champollion. Thefirst to arrive in Europe (after the diminutive Philae/Bankes obelisk, see above) was the westernmost of thepair of obelisks inscribed for Rameses II that still stoodbefore the great entrance pylon of the Temple ofAmun-Ra at Luxor. Selected as the most beautifulspecimen available on the authority of Champollionhimself, the 246-ton obelisk was lowered using anelaborate hinged device and loaded onto a speciallydesigned ship for transport to Paris, where it wasraised with great ceremony in the Place de la Concordein 1833 (Lébas 1839; Habachi 1984: 153–164;Porterfield 1998: 13–41; Hassan 2003). The next toarrive was the fallen one of the pair at the Caesareumin Alexandria, which had been offered to the Britishby the Egyptian authorities early in the century, butarrived only in 1878, after a tragic and nearlycatastrophic voyage in a specially designed bargecalled the Cleopatra. The obelisk was raised on theThames Embankment on September 13 of that year.The still-standing mate of this obelisk was offered atthis time to the United States, and its lowering andtransport were supervised by a naval officer andengineer named Henry H. Gorringe, who describedhis methods in a monumental tome that rivaled the earlyproduction of Domenico Fontana. The obelisk wasraised with great ceremony in New York’s Central Parkin the winter of 1881, where it remains today (Fig. 2).Obscured by trees and mostly ignored by strollers,

joggers, and the throngs who crowd the Egyptiancollections of the Metropolitan Museum of Art nearby,the New York obelisk provides a somewhat soberingcoda for the colorful history of these monuments,whose unique appeal made them the most admired anddesired of Egyptian inventions for some 2,000 years.

See also: ▶Pyramids in Egypt

AcknowledgmentsThe author wishes to acknowledge the useful sugges-tions provided by his colleagues, including PamelaLong, Anthony Grafton, Benjamin Weiss, JeffreyCollins, and Okasha El-Daly. All dates given forPharaohs and their Ptolemaic and Roman successorsfollow the chronology in Shaw (2000/2003: 480–489).

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1784 Obelisks in ancient Egypt

Bell, Lanny. The New Kingdom ‘Divine’ Temple: TheExample of Luxor. Temples of Ancient Egypt. Ed. ByronE. Shafer. Ithaca: Cornell University Press, 1997. 127–84.

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D'Onofrio, Cesare. Gli obelischi di Roma: storia e urbanis-tica di una città dall’ età antica al XX secolo. 3rd ed.Rome: Romana società editrice, 1992.

El-Daly, Okasha. Ancient Egypt in Medieval ArabicWritings. The Wisdom of Egypt: Changing VisionsThrough the Ages. Ed. Peter Ucko, Timothy Champion.London: UCL, 2003. 39–63.

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Fontana, Domenico. Della trasportatione dell’ obeliscoVaticano et delle fabriche di Nostro Signore Papa SistoV. [Rome: D. Basa, 1590]. Ed. Adriano Carugo. Milan: IlPolifilo, 1978.

Gorringe, Henry H. Egyptian Obelisks. New York: H.Gorringe, 1882.

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Habachi, Labib. The Obelisks of Egypt: Skyscrapers of thePast. Cairo: American University in Cairo Press, 1984.

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Schütz-Tübingen, Michael. Zur Sonnenuhr des Augustus aufdem Marsfeld. Gymnasium 97 (1990): 432–57.

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Observatories in India

VIRENDRA NATH SHARMA

India has an ancient astronomical tradition. Informationon its observatories is meager, however. It is certain thata number of prominent astronomers, patronized bykings, carried out their own observations, which arementioned in karan. as, or practical manuals. The placesof such observations, if operated for a reasonableperiod of time, technically could be called observa-tories. A court astronomer, Śan.karanārāyan.a (fl. 869),mentions such a place with instruments in the capitalcity of king Ravi Varmā of Kerala. Astronomers of theIslamic school of astronomy, such as ˓Abd al-Rashīdal-Yāqūtī (fifteenth century) report an observatory in

Observatories in India. Table 2 Instruments added after Saw

Instrument

1. Miśra yantra (Composite instrument)2. S’an

.ku yantra (Vertical staff)

3. Horizontal Scale (known as the seat of Jai Singh)

Observatories in India. Table 1 Inventory of Jai Singh’s ma

Instrument No

Dhruvadarśaka Pat.t.ikā (North Star Indicator) 1Nād. īvalaya (Equinoctial dial) 5Palabhā (Horizontal sundial) 2Agrā (Amplitude instrument) 5S’an

.ku (Horizontal dial) 1

Jaya Prakāśa (Hemispherical instrument) 2Rāma yantra (Cylindrical instrument) 2Rāśi valaya (Ecliptic dial) 12Śara yantra (Celestial latitude dial) 1Digam. śa (Azimuth circle) 3Kapāla (Hemispherical dial) 2Samrāt. (Equinoctial sundial) 6S.as.t.hām. śa (60 degree meridian chamber) 5Daks.inottara Bhitti (Meridian dial) 6

the city of Jājilī in India. The Emperor Humayun(d. 1556) is said to have had a personal observatory atKotah, near Delhi, where he himself took observations.An ambitious program of building observatories was

undertaken by Sawai Jai Singh (Savā’ī Jaya Sim. ha), anastronomer–statesman of India. Between 1724 and1735, Jai Singh built observatories at Delhi, Jaipur,Mathura, Varanasi, and Ujjain. His observatories,except for that of Mathura, still exist today in varyingdegrees of preservation. Sawai Jai Singh’s purpose inbuilding observatories was to update the existingplanetary tables. Toward this purpose, he designedand built instruments of stone and masonry. Theseinstruments may be classified into three main cate-gories based on their precision which varies anywherefrom ±1′ to a degree. Table 1 presents an inventory ofhis masonry instruments according to their precision,with the low precision instruments listed first. Table 2lists instruments added after Sawai Jai Singh’s death.Jai Singh constructed 15 different types of masonry

instruments for his observatories. Of these, the Samrāt.yantra, S.as.t.hām. śa, Daks.inottara Bhitti, Jaya Prakāśa,Nād. īvalaya, and Rāma yantras are his most importantinstruments.

Samrat. YantraThe Samrāt. yantra or the “Supreme Instrument” is JaiSingh’s most important creation. The instrument is

ai Jai Singh’s death

No. Location

1 Delhi1 Ujjain1 Jaipur

sonry instruments

. Location

JaipurJaipur (2), Varanasi, Ujjain, MathuraJaipur, UjjainDelhi, Ujjain, MathuraMathuraDelhi, JaipurDelhi, JaipurJaipurJaipurJaipur, Varanasi, UjjainJaipurDelhi, Jaipur (2), Varanasi (2), UjjainDelhi, Jaipur (4)Delhi, Jaipur, Varanasi (2), Ujjain, Mathura

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Observatories in India. Fig. 1 Samrāt yantra: principleand operation.

Observatories in India. Fig. 2 Jaipur Observatory of SawaiSai Singh.

Observatories in India. Fig. 3 Jaya Prakāśa at Jaipur. TheNād. īvalaya is in the background.

1786 Observatories in India

basically an equinoctial sundial, which has been in usein one form or another for hundreds of years in differentparts of the world.

The instrument consists of a meridian wall ABC, inthe shape of a right triangle, with its hypotenuse or thegnomon CA pointing toward the north celestial poleand its base BC horizontal along a north–south line.The angle ACB between the hypotenuse and the baseequals the latitude λ of the place. Projecting upwardfrom a point S near the base of the triangle are twoquadrants SQ1 and SQ2 of radius DS. These quadrantsare in a plane parallel to the equatorial plane. The centerof the two “quadrant arcs” lies at point D on thehypotenuse. The length and radius of the quadrants aresuch that, if put together, they would form a semicirclein the plane of the equator.

The quadrants are graduated into equal-lengthdivisions of time-measuring units, such as ghat.ikāsand palas, according to the Hindu system, or hours,minutes and seconds, according to the Western system.The upper two ends Q1 and Q2 of the quadrants indicateeither the 15-ghat.ikā marks for the Hindu system, orthe 6 a.m. and the 6 p.m. marks according the Westernsystem. The bottom-most point of both quadrants, onthe other hand, indicates the zero ghat.ikā or 12 noon.The hypotenuse or the gnomon edge AC is graduated to

read the angle of declination. The declination scale is atangential scale in which the division lengths graduallyincrease according to the tangent of the declination.

The primary object of a Samrāt. is to indicate theapparent solar time or local time of a place. On a clearday, as the sun journeys from east to west, the shadow ofthe Samrāt. gnomon sweeps the quadrant scales belowfrom one end to the other. At a givenmoment, the time isindicated by the shadow’s edge on a quadrant scale.

The time at night is measured by observing the hourangle of the star or its angular distance from themeridian.Because a Samrāt., like any other sundial, measures thelocal time or apparent solar time and not the “StandardTime” of a country, a correction has to be applied to itsreadings in order to obtain the standard time.

To measure the declination of the sun with a Samrāt.,the observer moves a rod over the gnomon surface ACup or down until the rod’s shadow falls on a quadrantscale below. The location of the rod on the gnomon scalethen gives the declination of the sun. Declinationmeasurement of a star or a planet requires the collabora-tion of two observers. One observer stays near thequadrants below and, sighting the star through a sightingdevice, guides the assistant, whomoves a rod up or down

Observatories in India. Fig. 4 The principle of a Rāmayantra.

Observatories in India 1787

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along the gnomon scale. The assistant does this until thevantage point V on a quadrant edge below, the gnomonedge above where the rod is placed, and the star – allthree – are in one line. The location of the rod on thegnomon scale then indicates the declination of the star.

S. as.t.ham.sa

A S.as. t.hām. śa yantra is a 60° arc built in the plane

of meridian within a dark chamber. The instrument isused for measuring the declination, zenith distance,and the diameter of the sun. As the sun drifts acrossthe meridian at noon, its pinhole image falling on theS.as.t.hām

. śa scale below enables the observer to measurethe zenith distance, declination, and the diameter ofthe sun. The image formed by the pinhole on the scalebelow is usually quite sharp, such that at times evensunspots may be seen on it.

Daks.inottara Bhitti YantraDaks.inottara Bhitti yantra is a modified version of themeridian dial of the ancients. It consists of a graduated

quadrant or a semicircle inscribed on a north–southwall. At the center of the arc is a horizontal rod. Theinstrument is used for measuring the meridian altitudeor the zenith distance of an object such as the sun, themoon, or a planet. According to Jagannātha Samrāt.,this was the instrument with which Jai Singhdetermined the obliquity of the ecliptic (the band ofthe zodiac through which the sun apparently moves inits yearly course), to be 23°28′ in 1729.

Jaya PrakasaThe Jaya Prakāśa is a multipurpose instrumentconsisting of hemispherical surfaces of concave shapeand inscribed with a number of arcs. These arcs indicatethe local time, and also measure various astronomicalparameters, such as the coordinates of a celestial bodyand ascendants, or a sign on the meridian. JayaPrakās’a represents the inverted image of two coordi-nate systems, namely, the azimuth-altitude and theequatorial, drawn on a concave surface. For theazimuth-altitude system, the rim of the concave bowlindicates the horizon. Cardinal points are marked onthe horizon, and crosswires are stretched between them.On a clear day, the shadow of the crosswire falling onthe concave surface below indicates the coordinates ofthe sun. Time is read by the shadow’s angular distancefrom the meridian along a diurnal circle.The instrument is built in two complementary halves,

giving it the capacity for night observations. In the twohalves the area between alternate hour circles is removed,and steps are provided in its place for the observer tomove around freely for his readings. The space betweenidentical hour circles of the two hemispheres is notremoved, however. The sections left behind in thehemispheres complement each other. They do so in sucha way that, if put together, they would form a completehemispherical surface. For night observations theobserver sights the object in the sky from the spacebetween the sections. The observer obtains the object inthe sky and the crosswire in one line. The coordinatesof the vantage points are then the coordinates of the objectin the sky. Jai Singh built his Jaya Prakās’as only at Delhiand Jaipur. These instruments survive in varying degreesof preservation. The instrument atDelhi has a diameter of8.33 m and that at Jaipur, 5.4 m.

Nad. ıvalayaA Nād. īvalaya consists of two circular plates fixedpermanently on a masonry stand of convenient heightabove ground level. The plates are oriented parallel tothe equatorial plane, and iron styles of appropriatelength pointing toward the poles are fixed at theircenters. The instrument Nād. īvalaya is, in fact, anequinoctial sundial built in two halves, indicating theapparent solar time of the place.

1788 Observatories in the Islamic world

The Nād. īvalaya is an effective tool for demonstrat-ing the passage of the sun across the celestial equator.On the vernal equinox and the autumnal equinox therays of the sun fall parallel to the two opposing faces ofthe plates and illuminate them both. However, at anyother time, only one or the other face remains in thesun. After the sun has crossed the equator aroundMarch 21, its rays illuminate the northern face for sixmonths. After September 21, it is the southern face thatreceives the rays of the sun for the next six months. JaiSingh built Nād. īvalayas at each of his observatory sitesexcept Delhi.

Rama YantraThe Rāma yantra is a cylindrical structure in twocomplementary halves that measure the azimuth andaltitude of a celestial object, for example the sun. Thecylindrical structure of Rāma yantra is open at the top,and its height equals its radius. The accompanying figureillustrates its principle and operation. To understand theprinciple, let us assume that the instrument is built as asingle unit as illustrated.

The cylinder, as in the figure, is open at the top andhas a vertical pole or pillar of the same height as thesurrounding walls at the center. Both the interior wallsand the floor of the structure are engraved with scalesmeasuring the angles of azimuth and altitude. Formeasuring the azimuth, circular scales with theircenters at the axis of the cylinder are drawn on thefloor of the structure and on the inner surface of thecylindrical walls. The scales are divided into degreesand minutes. For measuring the altitude, a set ofequally spaced radial lines is drawn on the floor.

These lines emanate from the central pillar andterminate at the base of the inner walls. Further, verticallines are inscribed on the cylindrical wall, which beginat the wall’s base and terminate at the top end. Theselines may be viewed as the vertical extension of theradial lines drawn on the floor of the instrument.

In daytime the coordinates of the sun are determinedby observing the shadow of the pillar’s top end on thescales, as shown in the figure. The coordinates of themoon, when it is bright enough to cast a shadow, mayalso be read in a similar manner. However, if themoon isnot bright enough, or if one wishes to measure thecoordinates of a star or planet that does not cast a shadow,a different procedure is followed. To accomplish this,the instrument is built in two complementary units.

The two complementary units of a Rāma yantra maybe viewed as if obtained by dividing an intactcylindrical structure into radial and vertical sectors.The units are such that if put together, they would forma complete cylinder with an open roof. The procedurefor measuring the coordinates at night with a Rāmayantra is similar to the one employed for the Jaya

Prakāśa. The observer works within the empty spacesbetween the radial sectors or between the walls of theinstrument. Sighting from a vacant place, he obtainsthe object in the sky, the top edge of the pillar, and thevantage point in one line. The vantage point afterappropriate interpolation gives the desired coordinates.If the vantage point lies within the empty spaces of thewalls, well above the floor, the observer may have to siton a plank inserted between the walls. The walls haveslots built specifically for holding such planks.

See also: ▶Jai Singh, ▶Gnomon in India, ▶Time

References

Ansari, S. M. Razaullah. Practical Astronomy in Indo-PersianSources. Indian Journal of History of Science 37 (2002).255–65.

Garrett, A. and Chandradhar Guleri. The Jaipur Observatoryand Its Builder. Allahabad: Pioneer Press, 1902.

Kaye, G. R. The Astronomical Observatories of Jai Singh.New Delhi: Archaeological Survey of India. Rpt. 1982.

Sarma, Sreeramula Rajeswara. Yantraprakāra of Sawai JaiSingh. Supplement to Studies in History of Medicine andScience. Vols. X and XI. 1986, 1987.

Sharma, Virendra Nath. Sawai Jai Singh and His Astronomy.New Delhi: Motilal Banarasidass, 1995.

Sharma, Virendra Nath. Sawai Jai Singh and His Observa-tories. Jaipur: Publication Scheme, 1997.

Observatories in the Islamic World

GREGG DE YOUNG

The observatory in Arabic/Islamic civilization under-went considerable elaboration from its beginning asa follower of earlier Greek observational posts. Theobservational instruments used must have been ver-sions of Ptolemaic (Greek) equipment:

. The meridian armillary, for determining solsticepoints and the obliquity of the ecliptic

. The plinth, used for the same purposes

. The equinoctial armillary, to determine equinoxpoints

. The “parallactic instrument” (or “Ptolemy’s Rulers”)to determine elevation in relation to the zenith, whenheavenly bodies reach culmination

. The armillary or spherical astrolabe, for measuringpositions of heavenly bodies relative to fixed orknown celestial objects

In the centuries that followed, the physical equip-ment of observatories underwent continuous evolution.Arabic/Islamic observers required precision in their

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work and usually tried to obtain it by increasing the sizeof instruments. Large instruments had to be carefullyfixed in place and required skilled craftsmen for theirconstruction and maintenance, as well as a staffof observers and mathematicians skilled in reducingthe observational data to mathematical models. Ingeneral, observation programs were initiated forcorrecting or improving the accuracy of existingastronomical tables (zīj). The production of a zīj wasuseful, not only for astrological/astronomical predic-tions, but also for encouraging the collection of datathat could support alternative cosmographical schemesthat avoided the embarrassment of Ptolemy’s equanttheory, especially in centers such as Marāgha.

Most observatories, because their operation involvedproduction and use of large and expensive instruments,were supported by state funds, although there is someevidence that private institutions existed as well, suchas the observatory of al-Battānī (d. 317 AH/AD 929) atRaqqa. The majority, however, survived at the mercy oftheir royal patrons. It was very rare for an observatory,such as the institution at Marāgha, to be assigned waqfincome. Since the waqf was intended to be a grant ofproperty in perpetuity for the sake of generating incomefor charitable institutions, the observatory at Marāgha(as well as one in Tabriz) must have been seen asproviding an essential public service, perhaps througheducational programs.

The first true observatories were founded underthe patronage of the ‘Abbāsid Caliph al-Ma’mūn(198–218 AH/AD 813–833), who also supportednumerous translations from Greek into Arabic. TheShammāsiyya (in Baghdad) and Mount Qāsīyūn (nearDamascus) observatories operated for a year, it seems.Although the sites may have lacked purpose-builtstructures, both employed permanent observationalstaff and instrument makers and technicians. Theirpurpose appears to have been the collection of accurateobservations of sun and moon only, although there aresome records of other observations. These observationswere presented in the Zīj Mumtah. an.

Sharaf al-Dawla (372–378 AH/AD 982–989) builtan observatory in the garden of his Baghdad palace. Itwas housed in a purpose-built structure and equippedwith instruments, some of which seem to have beenquite large. This institution marks an advance in severalrespects (1) it had a specific physical structure, (2) ithad as director/administrator, Abū Sahl al-Qūhī, afamous geometer and astronomer, in addition to a staffof astronomers and technicians, and (3) its researchprogram involved collecting data on the motions of allplanets. Its activities began with great fanfare, but seemto have died out quickly, perhaps due to the death of theroyal sponsor.

The observatory at Marāgha, founded by the Mongolconqueror-prince, Hūlāgū, was one of the biggest and

best equipped observatories prior to the modern era.Founded in 657 AH/AD 1259, the construction wasoverseen by Mu’ayyad al-Dīn al-’Urd. ī, from whoseautobiographical account we learn many details aboutthe observatory and its operation. The physical plantincluded several purpose-built structures and an exten-sive collection of instruments, many of them large.There are also reports of an extensive library. The staff,under the direction of Nas.īr al-Dīn al-T. ūsī, included anumber of leading mathematicians and astronomersfrom all parts of the Islamic world and beyond. (Thereare even reports of Chinese astronomers visiting andassisting at this observatory.) Once again, the purposewas to acquire the most accurate observational data inorder to correct earlier astronomical tables. The resultwas the Zīj Ilkhānī, completed in 670 AH/AD 1271.After completion of these tables, work on the site seemsto have slowed, although the institution continued toexist for at least three more decades.Another major observatory was founded in

823 AH/AD 1420 in Samarqand by Ulugh Beg,governor of Khurasān, who was himself well versedin mathematics and astronomy. Like the Marāghaobservatory, it had a staff of mathematicians, observa-tional astronomers, instrument makers, and techni-cians, although it seems to have been a more compactoperation. The most famous of its instruments was ahuge meridian arc enclosed within a large masonrystructure. The observatory enjoyed the active supportand participation of Ulugh Beg until his assassinationin 853 AH/AD 1449. Thus, it functioned for nearly 30years, during which time the Zīj-i Jurjānī, which waswidely circulated in Arabic, Persian and Turkish, wasproduced. Not only was this one of the longest-lived ofall Islamic observatories, it was also the site of the mostextensive collection of data on the fixed stars everattempted in the Arabic/Islamic world.In 983 AH/AD 1575, Taqī al-Dīn Muh.ammad

al-Rashīd ibn Ma’rūf, with the support of the OttomanGrand Vizier, successfully petitioned the Sultan forpermission to build an observatory in Istanbul in orderto produce a new set of astronomical tables, the oldertables being inaccurate and in need of revision. Hisrequest was successful and, in 985 AH/AD 1577, theIstanbul Observatory, with Taqī al-Dīn as its head,began operations. Like its predecessors, this institutionhad a permanent building housing observationalinstruments, a staff of astronomers and supportpersonnel, and a library. Three years after its inception,the observatory was demolished. Contemporary reportsdiffer on whether this action was undertaken with orwithout the support and encouragement of Taqī al-Dīn.Debate also continues about the possible influence ofhis account of observatory organization and instrumentconstruction on Europe’s greatest naked-eye observer,Tycho Brahe.

1790 Optics in China

With the destruction of the Istanbul observatory, thegreat premodern period of observatory constructioncame to an end. The observatories of Jai Singh II,Maharaja of Jaipur (AD 1686–1740) at best representthe dying embers of the tradition. These five observa-tories (located at Jaipur, Delhi, Benares, Ujjayin, andMathura) contained enormous masonry instruments,many still extant today. Jai Singh’s Zīj-i Muh. ammadShāhī, named after the emperor to whom it wasdedicated, was largely patterned after the earlier workof Ulugh Beg. This has prompted some to conclude thatthese late observatories mark a period of decadence andderivative astronomy. This judgment is probably tooharsh. These observatories, begun nearly a century afterthe founding of the Paris Observatory (which marks thebeginning of a new era in astronomical technique andorganization in support of a new interpretation ofcelestial phenomena) stand today as monuments to abrilliant, but now abandoned, intellectual, and socialtradition within the history of science.

See also: ▶al-Ma’mūn, ▶Armillary Spheres, ▶Astro-labe, ▶Astronomical Instruments, ▶Zīj, ▶Astronomy,Astrology, ▶al-Battānī, ▶Marāgha, ▶Ulugh Beg,▶Taqī al-Dīn, ▶Jai Singh

References

Kaye, J. R. The Astronomical Observatories of Jai Singh.Calcutta: Archaeological Survey of India, 1918.

Kennedy, E. S. A Survey of Islamic Astronomical Tables.Transactions of the American Philosophical Society, NewSeries 46 (1956): 123–77.

Mordtmann, J. H. Das Observatorium des Taqi ed-din zuPera. Der Islam 13 (1923): 82–96.

Sayılı, Aydın. The Observatory in Islam and its Place in theGeneral History of the Observatory. 2nd ed. Ankara: TurkTarih Kurumu Basimevi, 1988.

Sedillot, A. Mémoire sur les instruments astronomiques desarabes. Mémoires de l’Académie Royale des Inscriptionset Belles-Lettres de l’Institut de France, Série I. 1 (1884):1–229.

Seeman, H. Die Instrumente der Sternwärter zu Maraghanach den Mitteilungen von al-’Urd. ī. Sitzungberichte derphysikalisch-medizinischen Sozietät zu Erlangen 60(1928): 15–128.

Optics in China

Optics in China. Fig. 1 Water mirror. The water surface wasutilized as a reflecting surface. Such a water mirror was calledJian.

JINGUANG WANG, CAIWU WANG

Before AD 1911, optics in China went through fourstages. The first stage was from remote antiquity to theSpring and Autumn Period (770 BCE), the second

ended in AD 220 (end of the Dong Han Dynasty), thethird ended in AD 1380 (end of the Yuan Dynasty), andthe fourth stage ended in 1911 (end of the QingDynasty).

In the first stage, the Chinese began to develop aphilosophy of nature. The ideas of optics were in theirinfancy. In remote antiquity, the Chinese germinatedbasic knowledge of light sources, vision, shadowformation, and reflection. In addition, there were someinventions such as artificial light sources and reflectors.The artificial light sources or fire source were obtainedfrom striking stones, drilling wood, and focusingsunlight. The reflectors included water mirrors whichwere plane mirrors (Fig. 1) and bronze mirrorswhich were plane mirrors and convex mirrors. Eventhough all these achievements were superficial, theylaid foundations for later studies on shadow formationand optical images.

The second stage took place within an importantperiod for Chinese science and technology. During thattime, optical technology developed very rapidly. As anexample, techniques to make mirrors matured. Numer-ous studies led to deep understandings of lightreflection and rectilinear propagation as recorded inthe Mo Jing (Mohist Canon), which was writtenbetween 450 and 250 BCE. There were eight sectionsin the book:

1. Processes of shadow formation and vanishing2. Umbras and penumbras

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3. Rectilinear propagation of light and pinhole image4. Sunlight reflection and formation of an inverted

shadow5. Changes of shadow sizes (length and width)6. Image formation and symmetries due to plane

mirrors7. Two image variations from concave mirrors (erect

image and inverted image)8. One type of image formed by convex mirrors

These eight propositions systematically describedtheories in geometrical optics. Technically, Mo Jinghad achieved a level very similar to that of Euclid’sOptics.

During the third stage, Chinese scholars discoveredvarious optical phenomena. For example, aspects ofatmospheric optics were studied in detail, includinghalomaps and rainbow formation. Since image formationhad been a hot subject in Chinese optics, it was furtheradvanced during this stage. Most of the records can befound in a bookcalledMengxiBitan (MengXiEssays) bythe scientist ShenGuo (1032–1096), in the SongDynasty(960–1279). Among hundreds of sections in the book,there were more than ten dealing with optics. Sections 44and 330 are the most important. In Section 44, Shendiscussed image formation by pinhole and concavemirrors in terms of a terminology calledai, or pinhole andfocal point. He named such mathematical generalizationge shu. In Section 330, Shen discussed light penetratingmirrors, whichwere also called tou-guang jian or “magicmirrors.” There were more than 20 characters inscribedon amagicmirror.When sunlight shone on themirror, allthe characters were clearly projected on to a wall. Therewere three magic mirrors in Shen’s family. He also sawother mirrors in his friends’ homes. However, some otherextremely thin mirrors did not allow sunlight to passthrough. Themagicwas in the inscription of faint lines onthe back sideof themirror. (BasedonShen’s descriptions,modern Chinese shops are able to reproduce such magicmirrors by several techniques.) Besides those twosections, Shen presented quantitative relationships be-tween image sizes and curvatures of convex mirrors. Heintroduced a postmortem examinationmethod in which ared light was utilized. He also attributed rainbows to theshadows of the sun during rain.

After Shen’s work, another scientist, Zhao Youqin,carried out a famous optical experiment. Zhao lived inthe thirteenth century, and recorded this experimentin his book, Ge-Xiang Xin-Shu (New Astronomy). In achapter entitled “Pinhole Image,” Zhao detailed asystematic study carried out in a two story house. Therewere two rooms on the first floor, one on the left andone on the right. To make two light sources in these tworooms, two boards were “planted” with thousand ofcandles. On the top of each light board, an additional

covering board was placed. There was a hole in thecenter of the additional board. If the candles were lit,light could pass through the hole and then was projectedon to a screen. The screen was either the fixed ceiling oran adjustable screen suspended from the ceiling so thatthe distance between the light source and the screencould be adjusted. The following observations weremade in the experiment:

1. Shapes of the pinhole images are independent of theshapes and sizes of the small hole in the coveringboard.

2. The brightness of the image depends on the size ofthe hole. The larger the hole, the brighter the image.

3. When the source strength (number of candles)increases, the brightness of the image increases.

4. When the distance between the light source andthe image screen increases, the image brightnessdecreases.

Zhao’s experiment provided a lot of information onpinhole images. From the experiment, he proposed thisidea. On the image screen, there was a light spotcorresponding to a single candle. If a thousand candleswere lit on a source board, there would be a thousandimages of the candles. These images would overlapeach other. The final appearance of the image woulddepend on the distribution of lit candles. In addition tobasic optics, Zhao utilized his pinhole image theoryto study eclipses of the sun and the moon and otherastronomical phenomena.The fourth stage marked the end of traditional

Chinese optics. The new trend both continued theChinese system and adapted the Western systemimported from Europe. During this period, Fang Yizhi(1611–1671) wrote a book called Wuli Xiaozhi (SmallEncyclopedia of Physical Principles). In the book, Fangpointed out that light travels inwave forms, and he carriedout an experiment to study the diffraction of light.Several books and many articles on optics were

translated from Western languages to Chinese lan-guages, such as Yuan Jing Shuo (Telescopium) by theGermany Missionary Johanna Adam Schall Von Bell(1591–1666), and On Optics by Zhang Fuxi (d. 1862)and Englishman Joseph Edking (1823–1905). Anotherbook entitled Six Lectures on Light, written by Englishphysicist John Tyndall (1820–1893), was translated byCard T. Kreyer and Zhao Yuanyi in 1876.Several monographs on optics were written by

Chinese authors. In a book entitled Jingjing Lingchi(Treatise on Optics by an Untalented Scholar) byZheng Fuguang (b. 1780), geometric optics wassystematically introduced. In another monographentitled Geshu Bu (Supplement to Geometric Optics)written by Zou Boqi (1819–1869), optical theoremsand principles were discussed.

Optics in China. Fig. 2 Open-tube periscope in HanDynasty. This illustration is based on a description in HuaiNan Wan Bi Shu, a book published in Xi Han Dynasty.By hanging a big mirror on the top of a pole and using awater-reflecting surface, one could watch a neighbor’sactions. The object outside of the wall would form the imagein the mirror, which in turn would form another image byreflecting. In this illustration, a person inside is watching afarmer outside of the wall. This is actually the earliestperiscope in the world.

Optics in China. Fig. 3 Ice lens experiment. In Huai NanWan Bi Shu, there was a “miracle” experiment using an icelens. One would make a spherical lens with a piece of ice bypolishing both sides. Facing the lens to the sun and placing apiece of moxa at the focal point of the lens, one could lightthis piece of moxa.

1792 Optics in China

Several different kinds of optical instruments ordevices were improved. For instance, an optical expert,Sun Yunqiu (seventeenth century), made spectacles,telescopes, microscopes, and distorting mirrors.

The Chinese achieved high levels of understandingin optics, as illustrated by Mo Jing, Mengxi Bitan, andGexiang Xinshu. The ancient Chinese paid attention toboth theories and applications. A unique characteristicof Chinese optics is related to experimental approaches.All eight propositions in Mo Jing were based onexperimental observations. Between the Qing and HanDynasties, the Chinese mastered the concept of “focaldistance” when they ignited fires from a sphericalmirror. They created several novel devices such as theopen-tube periscope and ice lens. Both devices wererecorded in a book entitled Huai Nan Wan Bi Shu,published in Xi Han Dynasty. The open-tube periscopeconsisted of a big mirror, a basin filled with water, and apole. As shown in Fig. 2, by hanging the big mirror onthe top of the pole, one could watch the actions of theneighbors with the water surface. To make a sphericalice lens, one would use a piece of ice and grind it into aproper shape. As shown in Fig. 3, one could hold theice lens toward the Sun and place a piece of moxa(mugwort, or artemesia vulgaris) at the focal point.Thus, this piece of moxa could be lit. Chinese observedsimilarities among rainbows, waterdrop dispersion, andcrystal dispersion. Several Chinese scientists con-ducted high level experiments during their times, such

as the “spherical mirror images” experiment by ShenGuo, and the “pinhole images” experiment by ZhaoYouqin. The ancient Chinese optics system was basedon empirical observations, which was short of theoreti-cal abstraction and quantitative description. For exam-ple, no laws of reflection were proposed even after thephenomena of reflections had been observed for2,000 years. As Western optics was imported to China,the entire foundation of traditional Chinese optics waschanged.

References

Graham, A. C. and Nathan Sivin. A Systematic Approach toMohist Optics. Chinese Science. Ed. Shigera Nakayamaand Nathan Sivin. Cambridge, Massachusetts: MIT Press,1973. 105–52.

Needham, Joseph. Science and Civilisation in China. Vol. 4,Pt. 1. Cambridge: Cambridge University Press, 1962.78–125.

Wang, Jinguang. Zhao Youqin and His Research in Optics.Journal of the History of Science and Technology 12(1984): 93–9 (in Chinese).

---. Optics in China Based on Three Ancient Books. Scienceand Technology in Chinese Civilization. Ed. Cheng YihChen. New York: World Scientific Publishing, 1987.143–53.

Wang, Jinguang and Zhenhuan Hong. Story of Optics inAncient China. Shijiazhuang: Hebei People’s Publisher,1981 (in Chinese).

---. History of Optics in China. Changsha: Hunan EducationPublisher, 1986 (in Chinese).

Wang, Jinguang and Jun Wenren. The Scientific Achieve-ments of Shen Kuo. Research on Shen Kuo’s Work.Hangzhou: Zhejiang People’s Publisher, 1985. 64–123 (inChinese).

Optics in the Islamic world 1793

Optics in the Islamic World

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ELAHEH KHEIRANDISH

The science of optics entered the Islamic worldprimarily through Greek sources, during the ninthcentury transmission of ancient scientific and philo-sophical texts. As such, it was unlike other mathemati-cal sciences such as astronomy and algebra, whichbeing based on Indian and Persian sources as well,involved a “non-Western” intellectual and practicaldimension, in addition to physical and cultural settings.As further distinct from these and other fields, whatemerged as the so-called science of “aspects” or“optics” from a subdivision of Greek geometry,transformed its parent field quickly and significantly,starting with the translation of the relevant texts(Kheirandish 1996, 1999, 2001a). Indeed, if one fieldwere to be singled out in the Islamic world for havingleft the most influential mark on the development of adiscipline, this might be ‘ilm al-manāz. ir, as Greekoptika came to be called in Arabic. During the earliestphases of the discipline, a decisive theory about thenature and manner of vision, which was the mainsubject of optics for some time, developed after a longperiod of debate. The domain of the field also expandedfrom a geometrical study of vision to one into whichnot only theories of light, mirrors, rainbows, andshadows, but also the psychology of visual perception,were integrated as common subjects of investigation.Some of these added inquiries produced impressiveresults, but as the field turned from a branch ofmathematics into a discipline closer to physics, itsmethodology also left the purely geometrical world toenter an experimental realm.

Works that represent some highlights of thesedevelopments include the De aspectibus of Ya‘qūbal-Kindī (d. AD 870) (Rashed 1997, Adamson 2006),the Kitāb al-manāz. ir of Ibn al-Haytham (d. AD 1039),and its rich commentary, Tanqīh. al-manāz.ir of Kamālal-Dīn Fārisī (d. AD ca. 1320) (Schramm 1963, Sabra1989, 1994, 2002).

A supplementary list of optical works by these andother authors, composed in both Arabic and Persian,from the early ninth century all the way to abouthundred and fifty years ago, are representative of thequantitative developments of the field (Kheirandish1998, 2001b, 2002, 2004).

Disciplinary DevelopmentsOne would expect the science of optics to haveembraced a variety of phenomena from light andshadows, halos and rainbows, mirrors and burning

instruments, some observable from the beginning ofhuman history. But this was not always the case evenin ancient and medieval times. For ancient Greekscholars, from mathematicians such as Euclid (ca.300 BCE) and Ptolemy (second century AD), tophilosophers and physicians like Aristotle (ca. 400BCE) and Galen (second century AD), the focus ofwhat was called optika and classified under geometrywas vision, not light. Greek optics was primarilyconcerned with theories of vision, as the closeassociation of the term optika with the eye indicates,and in the case of the geometrical tradition in optics –the only tradition treating the subject in independentworks with that title – the proposed theories of visionwere even expressed in terms of visual rays (opseis)extending from the eye to the object. Greek writings didgo beyond the realm of direct vision, to includereflection from a polished surface (as in Euclid’sOptics, or Hero of Alexandria’s Catoptrics) orrefraction through a different medium (as added inPtolemy’s Optics). But works titled Optika still dealtprimarily with vision – leaving the domain of the fieldlargely determined by the relevancy of its subjectsto what was long considered the “most noble ofthe senses.”Early Islamic scholars inherited this particular

orientation, which initially determined the focus oftheir own optical inquiries, even the classification andstudy of related subjects concurrently received fromancient sources, from reflection and refraction toshadows, rainbows, colors, sighting instruments, andburning mirrors. But there was soon a considerablechange in optics’ scope and profile. With the Optics ofIbn al-Haytham (also known as Alhacen or Alhazen,ca. eleventh century AD) the extended disciplinaryboundaries left an immediate trace on subsequentdevelopments of a field, now called Perspectiva, onethat was largely carried over to the seventeenth centurywhen optics acquired its current name and generalcharacter.The change in the scope of ‘ilm al-manāz. ir, which

occurred alongside other theoretical and methodologi-cal developments, was itself a gradual process. Majorworks on optics proper, often identifiable by the termal-Manaz.ir in their titles (corresponding to the Optikain the titles of Euclid’s and Ptolemy’s texts), slowlycame to expand the meaning of the study of vision.Works from the De aspectibus (Ikhtilāf al-manāz. ir?) ofYa‘qūb al-Kindī (d. AD 870) and Kitāb al-manāz. ir ofIbn al-Haytham, to Tanqīh. al-manāz. ir of Nas.īr al-Dīnal-T. ūsī (d. AD 1274) and Tangīh. al-manāz.ir of Kamālal-Dīn Fārisī (d. AD 1320), spanning a period of about500 years, well represent the changing disciplinaryboundaries. Al-Kindī included in his De aspectibussurviving only in Latin a range of related discussionsfrom shadows and mirrors to the clarity of perception,

1794 Optics in the Islamic world

but left a number of others out. Ibn al-Haythamdiscussed in the seven books of his Kitāb al-Manāz.ir awide range of other subjects: the properties of light (andcolor) (Book 1), visual perception and visual illusions(Books II and III), and reflection and refraction (Books4–7), but wrote separately on burning instruments,halos and rainbows, or camera obscura. Kamāl al-DīnFārisī’s critical study of this same work, supplementedby a few of Ibn al-Haytham’s independent opticalwritings (On the Quality of Shadows, On the Form ofthe Eclipse, and On Light), together with an examina-tion of his own treatises (On Burning Sphere and Onthe Rainbow and Halo), expanded the topical range ofhis Tanqīh. al-manāz. ir to include all but the study ofburning mirrors. The disciplinary developments arealso reflected through a variety of related sources. Al-Fārābī’s (d. AD 950) Ih. s.ā’ al-‘ulūm (Enumeration ofthe Sciences) describes i˓lm al-manāz. ir as includingnot only the science of mirrors (‘ilm al-marāyā), butalso such topics as the vision of distant objects and theapplication of vision in surveying. At the same time asthe combination of the subjects of mirrors, or evenburning mirrors with that of vision was not souncommon, treatments of what are now consideredoptical problems often appeared in their own “properplace.” Thus theories of light and perception weretreated in philosophical works (following Aristotle), asin the related works of Ibn Sīnā (Avicenna, d. AD1037), or Ibn Rushd (Averroes, d. AD 1198). Treat-ments related to the anatomy of the eye appeared inmedical treatises (following Galen), as in the works ofH. unayn ibn Ish.āq (d. AD 877). Such subjects asburning instruments were more commonly treated aspart of the respective traditions of Diocles andAnthemius on Burning Mirrors, as in the case of AbūSa d˓ Ibn Sahl (ca. AD 984). Shadows continued to betreated in books called kutub al-az. lāl (Books onShadows), as in Bīrūnī’s (d. AD 1048) work devotedto this subject, and halos and rainbows often appearedin meteorological and astronomical literature, as in thecase of Ibn Sīnā and Qut.b al-Dīn Shīrāz. ī (d. AD 1311).It was not until the conscious effort of Shīrāz. ī’s student,Kamāl al-Dīn Fārisī, that most of these subjects wereintegrated into optics Sabra 1987a, 1987b, 1989.

Theoretical DevelopmentsAt the very beginning of the text which set out to placethe science of optics on a new foundation and wasinstantly recognized and utilized as the most completework on the subject in Europe, Ibn al-Haytham wrote:“For two opposite doctrines, it is either the case thatone of them is true and the other is false; or they areboth false,… the truth being other than either of them;or they both lead to one thing which is the truth each ofthe groups holding the two doctrines must have fallen

short of completing their inquiry” (Sabra 1989). Here,Ibn al-Haytham was reflecting on a long controversy invisual theory, which had taken shape between themathematicians and physicists before him and forwhich he managed to find a lasting solution.

The Greek mathematicians had explained visionthrough the assumption of visual rays extended fromthe eye towards the visual object. The best knownamong these were Euclid, whose Optics represents ageometrical approach to the study of vision, andPtolemy, who had added an experimental and psycho-logical dimension in his own Optics. The Galenicversion of the visual-ray hypothesis as contained in Deusu partium included the anatomical aspects of visionand stressed the role of medium through its ownphysiological approach. So did, Aristotle’s language ofthe reception of forms which was more adopted by thephysicists, or natural philosophers, in matters regardingvision. Islamic theorists writing in the tradition ofeach of the major Greek philosophers on vision didnot always fall strictly into one group or another(Lindgberg 1978). The visual-ray theorists (as.h.āb al-shu‘ā) and the upholders of the theory of forms (as.h.ābal-int.ibā‘), to which Ibn al-Haytham repeatedly refersin his search for a systematic solution, often consistedof more than one group. The first included in additionto mathematicians (ta‘limiyyūn), the followers of Platoor Galen or even theologians (mutakkalimūn), whileits immediate rival, natural philosophers (t.abī‘iyyūn)covered both Aristotelians and atomists. The illumina-tionists (ishrāqiyyūn), who proposed an alternative formof perception altogether, had their own forms andvariations. Ibn al-Haytham’s solution to many complexproblems raised by the first two groups was not only anattempt to determine such central questions as thedirection of radiation in vision. The significance of hismost celebrated work, Kitāb al-Manāz. ir, goes muchbeyond treatments of the problems of vision. Havingbeen translated into Latin in the late twelfth or earlythirteenth century and then into Italian in the fourteenthcentury, with a printed Latin version in the sixteenthcentury, the book had an impact on the epistemology oflate medieval Europe, the linear perspective of Renais-sance artists, and study of light all the way to theseventeenth century, with a list of figures includingRoger Bacon, Witelo, Pecham, Ockham, Oresme,Ghiberti, Snellius, Kepler, Descartes, Barrow, andHuygens. Ibn al-Haytham’s contribution to the studyof light included the assumption that light requiresa body (a medium) for its transmission, that itsmovement from the object to the eye is not of infinitespeed, though too quick to be perceived by sense, andit is “easier” and “quicker” in rarer media. His non-traditional conception of a finite, imperceptible intervalof time for the movement of light was defended andadvanced by a few in the Latin West, and his appeal to

Optics in the Islamic world 1795

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mechanical analogies to explain reflection and refrac-tion were adopted by many later thinkers (Sabra 1962,1967). The earlier independent researches of the tenthcentury mathematician Abū Sa‘d Ibn Sahl and hisanticipation of Snell’s law have been the subject of arecent study (Rashed 1993). Earlier developments uponwhich Ibn al-Haytham’s concepts of light and vision areclearly dependent include a principle now referred to asthe “punctiform analysis of light radiation” (Lindberg1976, Adamson 2006). An ancient conception based onrectilinear radiation, it grew on the assumption of a one-to-one correspondence between points on a visiblesurface and the eye, laying the foundation for thegeometry of sight of the Western perspectivists and ofKepler. The principle can already be traced not only inthe works of earlier Arabic authors such al-Kindī, buteven in the way Euclidean assumptions were translatedinto Arabic, thereby stretching the period and impor-tance of theoretical developments to the early ninthcentury. Immediate preoccupation with crucial ques-tions about the exact nature of visual clarity and thestructure of the visual cone (the role of central ray, theshape of its base), goes back to this same early period.Sometimes, concepts were positively affected by theadopted Arabic terminology: the expression for visual“clarity,” for example (kathrā, also meaning multitudeand magnitude), led to questions that were themselvesthe staring points for many later discussions inmedievalEurope.Other times,word choices had anopposite effect:in the case of “refraction”, the non-standard adoption ofits terminology (in ‘itāf) for reflection (in‘ikās), led to aparticularly problematic treatment of indirect vision (i.e.vision through mediums), in addition to the poorreception of the relevant parts of the Optics of bothPtolemy and Ibn al-Haytham in some parts of the Islamicworld (Kheirandish 1996, 2004). But the limitedunderstanding of concepts such as “refraction” did notprovide a major obstacle for important theoreticaldevelopments later, including the correct explanationof the theory of rainbow formation. Explanations of theprimary and secondary bows in terms of the refraction oflight in raindrops were offered by Qut.b al-Dīn Shirāzīand later refined through experimental means by hisown student, Kamāl al-Dīn Fārisī in Islamic Persia,almost at the same time asTheodoric of Freiberg’s (d. ca.AD 1310) theory of rainbows was being offered. Amajor obstacle, however, did prevent proper treatmentof inverted images within the eye in direct vision (i.e.vision through air), an obstacle occasioned by physio-logical shortcomings in Ibn al-Haytham’s otherwise“revolutionary” achievements in optics (Sabra, 2002).Kepler’s much later treatments provided the necessarybreakthroughs in involving upright retinal images andfocal properties of lenses; but they are also notable forrepresenting theories of vision and light in a manner thathas made their respective treatments viewed as a

continuation and break with the past, depending ontheir perceived stress on vision and light respectively(Lindberg 1976; Smith, 2004). The earlier Islamicauthors, both before and after Ibn al-Haytham, havetheir own share of historical achievements and con-tributions: they not only changed the face of thetheoretical and disciplinary problems in optics, theyalso lay new methodological standards for opticalinquiries.

Methodological DevelopmentsThe historical relationship between the sciences ofoptics and astronomy had a particularly importanteffect on the development of the methodologicaldimensions of the field. Euclid’s Optics was amongthe Intermediate books (mutawassit.āt), studied after hisown Elements and before Ptolemy’s Almagest. Butoptics was also to borrow from astronomy, though in amarkedly different form and pace. The notion of i‘tibār(experiment) was adopted and transformed by Ibnal-Haytham from astronomical works to be used inoptics, as a methodological measure to replace geomet-rical demonstrations related to light and vision withexperimental ones (Sabra 1971, 1994). This, however,occurred only after the old Aristotelian superior–subordinate relationship of disciplines was replacedfirst by their cooperation (ishtirāk) (in the ninthcentury), and then by their combination (tarkīb) (in theeleventh century). So the full service of astronomy tooptics came relatively late. The imported experimentaldimension was a significant step for the methodologicaltransformation of the science of optics (Sabra, 1989).Before this transformation, the discipline’s methodi-

cal guidelines relied heavily on the teachings ofAristotle. For Aristotle, optics was a branch of geometryand one of “the more physical of the mathematicalsciences” (Physics, 194a 6–11). Themethod of applyinggeometrical demonstrations to propositions on visionwas adopted by Euclid, and through him more directlyby Arabic optical authors. But alternative methodologi-cal approaches had already begun with a few earlyIslamic scholars. Al-Kindī, who reminded the reader inthe preface of his De aspectibus that “geometricaldemonstrations would proceed in accordance with therequirement of physical things,” supplied geometricaldemonstrations with experimental ones throughout histext. About the same time, Qust.ā ibn Lūqā spoke in atext on optics and its application to mirrors about “thecooperation” of natural philosophy (from which weacquire sense perception) and geometry (for itsgeometrical demonstrations). Even in the early text ofAh.mad ibn Í˓sā, specifically titled as being “in thetradition of Euclid,” Euclidean examples were some-times supplemented by “sense-based examples” – thoseto be set up (Kheirandish 2002).

1796 Optics in the Islamic world

Ibn al-Haytham would continue to regard experi-mental optics as a mathematical inquiry. But in thecourse of his attempt to examine the study of vision andits foundations, the methodology of the mathematicalscience of optics was to be transformed radically. Thesynthesis (tarkīb) of physics (involving questionsconcerning the nature of light), and mathematics(dealing with manner of its propagation), followinghis explicit division between physical (t.abī‘iyya) andmathematical (ta‘līmiyya) inquiries as two separatecriteria, was at the heart of a new methodology that wasto change the discipline. Ibn al-Haytham’s contempo-rary, Ibn Sīnā, adopted a somewhat different methodo-logical approach when he supplemented his criticalremarks on previous treatments of rainbows withdetailed observations of his own. Kamāl al-Dīn al-Fārisī, acknowledging the guidance of his predecessor,and inspired by his teacher, Qut.b al-Dīn al-Shīrāzī,added an unmistakably modern experimental touchto such observations. He reproduced an artificialobject, such as a spherical globe filled with water torepresent raindrops, as part of a conscious shift fromtraditional explanations of the phenomenon of therainbow in terms of clouds acting as a concave mirror,to one in terms of the passage of light through atransparent sphere. By this later period, the field notonly included subjects and theories more easilyassociated with optics today; it had also acquired themore modern methodological approach of “controlled”experimentation.

See also:▶al-Kindī, ▶Ibn al-Haytham, ▶Nas.īr al-Dīnal-T. ūsī, ▶Qust.ā ibn Lūqā, ▶Ibn Sinā, ▶Ibn Sahl, ▶al-Bīrūnī, ▶al-Shīrāzī, ▶H. unayn ibn Ish.āq, ▶Ibn Rushd,▶Physics

References

Primary SourcesEuclid. Euclidis Opera Omnia. Ed. J. Heiberg and H. Menge.Leipzig: Teubner, 1883–1916. English translation byH.E. Burton. The Optics of Euclid. Journal of the OpticalSociety of America 35 (1945): 357–72.

Ibn al-Haytham and Kitāb al-Manāz. ir. Eds. A. I. Sabra.Al-H. asan Ibn al-Haytham, Kitāb al-Manāz. ir: Books I–II–III : Edited with Introduction, Arabic–Latin Glossaries andConcordance Tables by Abdelhamid I. Sabra, Kuwait: TheNational Council for Arts and Letters, 1983; Translationand Commentary by A. I. Sabra. The Optics of Ibn al-Haytham. 2 vols. London: The Warburg Institute, 1989.

al-Fārisī, Kamāl al-Dīn. Tanqīh. al-Manāz. ir li-dhawī alabs.ārwa al-bas.ā’ir. 2 vols. Hyderabad: Mat.ba‘at Majlis Dā’īratal-Ma‘ārif, 1347–48 (1928–30).

al-Kindī. De aspectibus. Ed. Björnbo, Axel Anthon, andSebastian Vogl. Al-Kindi, Tideus und Pseudo-Euklid: DreiOptische Werke. Leipzig: Teubner, 1912.

Ptolemy. L’Optique de Claude Ptolémée. Ed. Albert Lejeune.Leiden: E. J. Brill, 1989.

Secondary SourcesPeter Adamson, “Vision, Light and Color in al-Kindi,Ptolemy and the Ancient Commentators,” Arabic Sciencesand Philosophy 16 (2006): 207–236.

Kheirandish, Elaheh. The Arabic Version of EuclideanOptics: Transformations as Linguistic Problems in Trans-mission, Tradition, Transmission, Transformation: Pro-ceedings of Two Conferences on Pre-modern Science.Heldat the University of Oklahoma. Ed. F. Jamil Ragep andSally P. Ragep with Stephen Livesy. Leiden, New York:E.J. Brill, Collection de Travaux de L’académie Inter-nationale D’histoire des Sciences, 1996.

---. The ‘Manåz. ir’ Tradition Through Persian Sources, Lessciences dans le monde iranien, Ed. Z. Vesel, H.Beikbaghban et B. Thierry de Crussol des Epesse (Actesdu Colloque Tenu à L’univrsité des Sciences Humaines deStrasbourg, 95), Tehran: Institut Français de Recherche enIran (IFRI), 1998: 125–45.

---. The Arabic Version of Euclid’s Optics: Kitāb Uqliīdis fiIkhtilāf al-manāz. ir, Arabic text and English Translationwith a Historical Commentary, Sources in the History ofMathematics and Physical Sciences, Ed. G. J. Toomer, no.16, 2 vols, New York: Springer-Verlag, 1999.

---. What ‘Euclid Said’ to His Arabic Readers: The Caseof the Optics, De Diversis Artibus (Collection ofStudies from the International Academy of the History ofScience), Ed. Gérard Simon and Suzanne Débarbat(Proceedings of the XXth International Congress ofHistory of Science. Liege, 1997), Belgium: Brepols55.18 (2001a): 17–28.

---. Optics: Highlights from Islamic Lands. The DifferentAspects of Islamic Culture, Vol. 4: Science and Technologyin Islam, Part I, Paris: UNESCO 2001b: 337–357.

---. The Many Aspects of Appearances: Arabic Optics to 950AD. The Enterprise of Science in Islam: New Perspectives.Ed. Jan P. Hogendijk and AbdelHamid Sabra (ConferenceProceedings, Dibner Institute, 1998) Cambridge: MITPress, 2002: 55–83.

---. The Puzzle of T. ūsī’s Optical Works. Les sciences dans lamonde iranien, Tehran: Institut Français de Recherche enIran (IFRI). Ed. N. Pourjavady et. Z. Vesel (CONFER-ENCE proceedings: Tehran, 1998) 2004: 197–213.

Lindberg, David, C. Theories of Vision from Al-Kindi toKepler. Chicago: University of Chicago Press, 1976.

---. The Intromission-Extramission Controversy in IslamicVisual Theory: Alkindi versus Avicenna, in Studies inPerception: Interrelations in the History and Philosophy ofScience, Ed. Peter K. Machamer and Robert C. Turnbull,Columbus: Ohio State University Press, 1978.

Meyerhof, Max. Die Optik der Araber. Zeitschrift fürophthal-mologische Optik 8 (1920):16–29, 42–54, 86–90.

Rashed, Roshdi. Optique et Mathématiques: Recherches surL’histoire de la Pensée Scientifique en Arabe. London:Variorum, 1992.

---. Géométrie et Dioptrique au Xe Siècle: Ibn Sahl, al-Qūhī,et Ibn al-Haytham. Paris: Les Belles Lettres, 1993.

---.Æuvres Philosophiques et Scientifique d’Al-Kindī, Vol. 1:L’Optique et la Catoptrique, Islamic Philosophy Theologyand Science, Ed. H. Daiber and D. Pingree, Leiden: Brill,1997.

Sabra, A. I. Explanations of Optical Reflection andRefraction: Ibn al-Haytham, Descartes, Newton. Actes duDixième Congres Internationale d’Histoire des Sciences.Ithaca 1962, 551–554.

Origami 1797

Sabra, Theories from Dexartes to Newton, London: Old-bourne, 1967, Cambridge; New York: Cambridge Univer-sity Press, 1981.

Sabra A.I., “The Astronomical Origin of Ibn al-Haytham’sConcept of Experiment,” Actes XIIe Congrès Internationald’ histoire des Science, Paris: Albert Blanchand, 1971:133–136.

Sabra, A. I. Manāz. ir, or ‘Ilm al-manāz. ir. In Encyclopaedia ofIslam, Vol. 6. Leiden: Brill 1987a: 376–377.

Sabra, A. I. Optics, Islamic. In Dictionary of the Middle Ages,Vol. 9. Ed. Joseph R. Strayer. New York: CharlesScribner’s Sons 1987b: 240–247.

Sabra, A. I. Optics, Astronomy and Logic: Studies in ArabicSciences and Philosophy. Aldershot, England: Variorum,1994.

Sabra, A. I. Ibn al-Haytham’s Revolutionary Project inOptics: The Achievement And The Obstacle. TheEnterprise of Science in Islam: New Perspectives, Ed.Jan P. Hogendijk and AbdelHamid Sabra (ConferenceProceedings, Dibner Institute, 1998), Cambridge: MITPress, 2002: 85–118.

Schramm, Matthias. Ibn al-Haythams Weg zur Physik.Wiesbaden: F. Steiner, 1963.

Smith, A. Mark. Alhacen’s Theory of Visual Perception: ACritical Edition with English Translation and Commentaryof the First Three Books of Alhacen’s De Aspectibus,the Medieval Latin Version of Ibn al-Haytham’s Kitāb al-Manāz. ir, 2 vols. Transactions of the American Philosophi-cal Society, 2001: 91, 4.

Smith, A. Mark. What is the History of Medieval OpticsReally About. Proceedings of the American PhilosophicalSociety 2004: 148, 2: 180–194.

Origami

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THOMAS HULL

Origami is the art of folding paper into works ofsculpture. No one knows when or where the art of paperfolding started, but many scholars believe that the

Origami. Fig. 1 Go-hei Paper Streamers at a Small Shinto Shrinpermission.

invention of paper in China around 100 BCE (see theInstitute of Paper Science and Technology website) hadto have coincided with the first attempts at paperfolding.However, while there is evidence of paper folding

developing around the world as paper making technol-ogy spread, it was the Japanese who embraced the artform as part of their culture. In fact, origami is aJapanese word made up of two characters: orumeaning“to fold” and kami meaning paper. The Japaneselanguage has many homonyms–words that sound thesame but mean different things. Kami is one such word;in addition to “fold” it also means “god” or “deity.”Some people have conjectured that this is not acoincidence, and that this reflects why the JapaneseShinto religion uses folded paper to symbolize thespirits of deceased relatives. However, the Japaneselanguage simply has so many homonyms that thismight actually be a coincidence.Records of ancient Japanese folding are hard to find.

Certainly by the Edo period (1603–1867) in Japannumerous paintings and woodcuts can be found depict-ing upper class women folding the traditional crane, ororizuru. Also in the 1800s a few books on recreationalorigami were produced in Japan. Most referenceshistorians have found to origami prior to the 1800s arereligious and cultural-based. As far back as the 1600sorigami butterflies were placed over the stoppers ofsake bottles for wedding ceremonies, and folded paperstreamers called go-hei were hung in Shinto temples torepresent spirits of the dead. Such streamers can still befound in modern Shinto shrines (Fig. 1).The fact that by the 1800s people in Japan were

folding paper recreationally, as opposed to only forceremonies and religion indicates that origami hadgrown into a standard art form by this time. It is in theEdo period that one finds references to the classicJapanese crane and frog models (Fig. 2). However,there is also evidence that some Edo-era Japanese

e Outside of Tokyo, Japan. Photo by Thomas Hull. Used with

Origami. Fig. 4 A More Intricate Origami sangaku.

Origami. Fig. 2 The Classic Japanese Frog and Crane(orizuru) Models. Photo by Thomas Hull. Used withpermission.

Origami. Fig. 3 The pentagon knot sangaku. “Construct aRegular Pentagon by Tying a Knot in a Strip of Paper ofWidth a. Calculate the Side t of the Pentagon in Terms of a.”(Fukawaga 1989: 49)

1798 Origami

origamists were exploring the science and mathematicsof paper folding –something which modern mathema-ticians have only been researching in depth for the past30 years. In Edo-era Japan there was a practice ofplacing artistically painted geometric problems onsmall wooden panels in Shinto temples. These tablets,called sangaku , were displayed to be read by the templevisitors as challenges to solve. This practice wasprevalent throughout Japan, and it indicates some levelof public interest and education in geometry –enough tosolve such problems recreationally in the same way thatpeople today buy puzzle books for mental challenges.In his book Japanese Temple Geometry Problems ,Hidetosi Fukagawa describes over 250 examples ofsangaku , some of which are extremely sophisticated.Two of his examples are based on origami. One, shownin Fig. 3, illustrates how to tie a strip of paper into apentagonal knot (Fukagawa 1989 : 49). The challenge isto prove that this knot makes a regular pentagon (allsides of equal length).

The second example, in Figure 4, shows a muchmore complicated instance of paper folding geometry.Here we are asked to take a square piece of paper andfold one corner to an arbitrary point on the oppositeside. The text of this sangaku is more elaborate.

A square sheet of paper ABCD is folded as shown inthe figure with D falling on D ′, which lies on BC , withA falling on A′, and A′D′ intersects AB at E. A circle isinscribed in triangle EBD′. Show that the radius of thiscircle is equal to A′E (Fukagawa 1989: 37).

Amazingly, the geometric principles at play in thesangaku of Figure 4 were independently discoveredover one hundred years later by Kazuo Haga, aJapanese teacher who specializes in origami geometry.In fact, the geometric property that triangles CD′G andBED′ and A′EF are all similar is known as Haga’sTheorem. That ancient paper folders were exploring thesame kind of origami geometry as modern investigators

is a testament to the powerful utility of origami as adevice for exploring mathematics.

The Meji Restoration (1866–1869) and aftermathsaw the decline of a number of classic Japanese arts,including origami. But the practice did continue, andafterWorldWar II origami emerged again as an art form.The most influential person in this effort was AkiraYoshizawa, who tried to popularize origami in hiscountry by creating hundreds of new models, holdingexhibitions, and creating the International OrigamiAssociation. He also began important correspondenceswith people from other countries, in particular LillianOppenheimer of New York, Robert Harbin of the UK,and Gershon Legman of France. This helped spread theart of origami to other countries, and these same peoplewere pivotal in the creation of the organizations OrigamiUSA, the British Origami Society, and the MouvementFrançais des Plieurs de Papier.

Origami 1799

Partly due to the work of these organizations, origamiart went through a renaissance in the late twentiethcentury. In 1979 American paper folder John Montrollpublished his first book (Montroll 1979) whichcontained origami models at a level of complexity neverbefore seen in the origami world. For the first time, paperfolders began to see that it was possible to, for example,fold a grasshopper, complete with six legs, wings,abdomen, thorax, head, and two antennae, all from asingle square of paper with no cuts involved. Thetechniques with which he used to do this, which blendedmethods from classic Japanese models with brand new

Origami. Fig. 7 Jun Maekawa’s Winged Demon (Kasahara et

Origami. Fig. 5 John Montroll’s Zebra Model (Montroll1991), Folded from a Square Sheet of Paper, Black onOne Side and White on the Other, with no Cuts.

Origami. Fig. 6 The Crease Pattern for the Classic FlappingBird.

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approaches, were mined by other origamists, startinga wave of complex-level origami design. Amongthe artists who emerged during this period was RobertLang, who began systematically, analyzing the mathe-matics behind such complex designs. In addition,numerous Japanese folders, like Jun Maekawa, FumiakiKawahata, and Toshiyuki Meguro, developed their ownmethods and raised the level of complex origami tonew heights (Fig. 5).These design methods can be understood by

considering the crease pattern of an origami model(Fig. 6). This is a diagram of a piece of paper with linesrepresenting the creases used in the final origamimodel. This can be thought of as a blueprint for thedesign. In particular, modern origami designers canplan their design by thinking of any appendage thatthey need, be it the leg of an insect or the head of ahorse, as requiring a circle of paper in the square to bedevoted to that appendage. In other words, that circle,when folded, can be thought to collapse like anumbrella to create the appendage. This turns origamidesign into a problem of packing circles of differentsizes into a square, and many modern origami designscan be analyzed in this way. Fig. 7 shows a model byJun Maekawa from the mid 1980s with its creasepattern and circle decomposition.Complex design methods have been developing and

becoming more popular in the origami communitysince the 1980s, culminating in Robert Lang’scompendium on the subject (Lang 2003), where hedescribes howmuch of origami design can be done on acomputer. Some origami artists have complained thatpaying such attention to complexity is forcing paperfolders to forget the more subtle, artistic expression thatorigami can achieve. Others have been using computermethods as a quick way to get a design, and then focuson artistry as they try to achieve this design in actualpaper. In any case it is clear that origamists today arefolding things that people 10 or 20 years ago neverwould have thought possible.

al, 1983) with its Crease Pattern and Circle. Decomposition.

1800 Origami

References

Engel, Peter. Origami from Angelfish to Zen. New York:Dover, 1994.

Fukagawa, Hidetosi, and Pedoe, Dan. Japanese TempleGeometry Problems.Winnipeg: Charles Babbage ResearchFoundation, 1989.

Kasahara, Kunihiko, and Maekawa, Jun. Viva! Origami.Tokyo: Sanrio, 1983.

Kasahara, Kunihiko, and Takahama, Toshie. Origami for theConnoisseur. Tokyo: Japan Publications, 1998.

Lang, Robert. Origami Design Secrets: MathematicalMethods for an Ancient Art. Natick: AK Peters, 2003.

Montroll, John. Origami for the Enthusiast. New York:Dover, 1979.

---. African Animals in Origami. New York: Dover, 1991.