242 LangLey et al.

A Comparison of Dating Techniques at Torre de Palma, Portugal: Mortars and Ceramics

Maia M. LangLey – Stephanie J. MaLoney – ÅSa RingboM – Jan heineMeieR – aLf LindRooS

The archaeological site of Torre de Palma, located in the township of Monforte in eastern Portugal, was first discovered in 1947 and excavated annually until 1965 (Fig. 1). As was the case with many archaeological sites in the early- and mid-twentieth century, Torre de Palma was excavated primarily by field hands who were from the local community. Field managers, who usually were employees and/or docents of the Museu Nacional de Arqueologia e Etnologia (MNAE), in Belem, Portugal, had limited formal education, excavation experience, or conservation training. Torre de Palma, the largest known Roman villa excavated in Iberia, has revealed a wealth of materials that give researchers in Romano-Lusitanian studies insight into the everyday activities and trade contacts in this rural area of Roman Lusitania.

Manuel Heleno directed the initial excavations at Palma from his chair in the national museum or from his residences in Lisbon and Monte Real. By means of letters and telegraphs he often simultaneously directed dozens of excavations in the north and south of Portugal. He rarely saw materials until they were shipped by train, weeks or months later, to the museum. As far as can be determined from notes and journal entries, he visited Torre de Palma no more than 10 times during the 18 years of MNAE excavations. Additional excavations were conducted in 1971-72 by Fernando de Almeida, also a director of the MNAE.1 These first 25 years of excavations revealed, among other things, an impressive pars urbana decorated with rich tapestries of floor mosaics and a pars rustica including a monumental press, two bath complexes, an unusual double-apsed paleo-Christian basilica and what is now thought to be an early monastic complex. In addition to these finds, the materials

1 For more detail on the history of the excavations, see M. LangLey, ‘Invisible Converts: Non-Visibility of Christian Culture at Torre de Palma (Monforte, Portugal)’, in IV Coloquio Internacional de Arqueologia en Gijón. Las villae tardorromanas en el occidente del Imperio. Arquitecturea y función, Gijón 2007, 639-646; R. MataLoto - M. LangLey - R. boaventuRa, ‘A necrópole sidérica de Torre de Palma (Monforte, Portugal)’, in a. JavieR JiMénez (ed.), Siderum Ana I, El río Guadiana en época post-orientalizante, (Anejos de Archivo Español de Arqueología XLVI) Mérida 2008, 284f.

AUGUSTA EMERITA OLISIPO(LISBON)

(MÉRIDA)

(SANT AREM)

(BEJA)

GALLAECIA

LUSITANIA

BAETICA

PAX JULIA

SCALLABIS

DE PALMATORRE

Figure 1. Map of Roman Portugal. Torre de Palma lies between Olisipo and Augusta Emerita.

Comm. Hum. Litt. Vol. 128 243

from this site include one of the largest known assemblages of metal tools and an amazingly well preserved osteological collection including more than 250 individuals. Missing, however, were the proveniences of materials collected during the early excavations and chronologies for all areas of the site. Why? In 1965, Heleno retired and took with him the records needed to decipher the results of most of the major excavations in Portugal conducted during his tenure as director of the MNAE. Because of the unscientific nature of the excavations, the loss of records, and the wealth of material found, the site was mythologized and, until recently, was thought to be a kind of “dead site” - one that could never be studied or scientifically or chronologically reconstructed.

1. the aMeRican excavationS

The University of Louisville Excavations were initiated in 1983 and continued until 2000. This series of campaigns began with the re-excavation of the unique basilica and nearby cemeteries. Because little information existed regarding the chronologies of the site or those materials retained from the earlier Portuguese excavations, the American team subsequently re-excavated the villa. Fortunately, that project yielded materials and new areas that had not been exposed during the MNAE campaigns.

All of the authors of this paper have been intimately involved with the Torre de Palma project and have worked, independently and together, on different aspects of its architecture and collections. Stephanie J. Maloney was director throughout the American campaigns while Maia M. Langley worked as a field supervisor from 1995 through 2000. After the completion of the excavations in 2000, Langley began inventorying materials from the Portuguese collections and studying materials from both excavations in order to comprehensively understand the corpus of materials from this site. Most relevant to this paper, she is responsible for the study of the terra sigillata and African Red Slip wares. Åsa Ringbom, Jan Heinimeier, and Alf Lindroos have been responsible for the mortar dating.

The analysis of materials from both campaigns reveals occupation periods from the Chalcolithic, Bronze, and Iron Ages, the Roman period through late antiquity and the twelfth through sixteenth centuries. This wide range of occupation contributes to an understanding of the continuity and merger of various peoples from Pre- and Proto-history and the absorption of Roman culture through late antiquity. The fact that this site flourished for nearly two thousand years, coupled with the existence of some unique architectural types makes it especially relevant and important to any studies concerning Romanization and Christianization as well as the evolution of villa and monastic culture in Iberia. It was because of the importance of the site and the unfortunate loss of the provenience of materials that could have been chronological indicators, that the mortar dating project at Torre de Palma was begun.

Another reason for the application of this technique here is the manner in which the major complexes of this site were excavated during the Portuguese campaigns. When the site was initially discovered in late February of 1947 by a farmhand, an undocumented excavation began and lasted for some weeks until Heleno implemented more organized

244 LangLey et al.

work. Even then the excavation techniques utilized were often loose and poorly controlled by the managers. Most of the archival information, such as plans, notes, field correspondence and journals, was missing for decades2 until, because of the perseverance of director Luis Raposo, they were re-acquired by the MNAE in 1997. In short, this site was over-excavated for decades by more than five field managers whose notes had been long-separated from the archaeological materials. If one considers the important periods represented by this site coupled with its over-exposed remains, it is not difficult to understand why creative and alternative methods of dating needed to be sought in order to answer the important questions: what was the floruit of this site and when, if ever, was it abandoned?

2. MoRtaR dating at toRRe de paLMa

In 1996 Dr Åsa Ringbom was a visiting professor of Art History at the University of Louisville, where Maloney was a professor specializing in the Late Antique and Medieval periods. Discussions between the two revealed a common interest - each wanted to date monuments for which little traditional chronological evidence was available. Ringbom explained the work she and her team were doing with the 14C dating of mortars in the Åland Islands of Finland. Maloney had taken mortar samples from Torre de Palma in hopes of establishing a relative chronology for these data through careful chemical analysis. In fact, this approach did help to identify relative phases of construction techniques and structures but did not help establish absolute dates. After learning that mortar samples were available, Ringbom had a few of those samples analyzed. The initial results were encouraging, and a mortar dating project was launched. Torre de Palma became the first testing ground for the application of this new method of 14C mortar dating of ancient sites.

Torre de Palma shares problems with many sites uncovered years ago. Many of these sites have been exposed to the elements for years with little or no upkeep or preservation. Some, like Palma, were degraded by exposure to the seasonal burning of grasses and weeds surrounding them. More to the point, reliable evidence for the dating of some buildings and complexes is scarce or lacking entirely. In some cases, the original context of stored materials cannot be identified with any precision; in others, few or no, datable artifacts were found. It is in this context that a successful means of dating mortars has the potential to be especially helpful.

Even if mortar is not an organic material, it can be dated through normal 14C analysis procedures. This is because mortar, when it hardens, absorbs the CO2 from the atmosphere and thereafter behaves as if it were organic. There are, however, risks involved. One of them is contamination from unburned limestone, which will yield ages too ancient. Another is re-crystallization of limestone, which is revealed in results too recent. To avoid this kind of contamination and to enrich the carbonate in the easily soluble mortar, samples go through different steps of preparation, both mechanical and chemical. In the chemical separation, 85% phosphoric acid is poured over the sieved sample under vacuum. The

2 LangLey (2007), cit. n. 1.

Comm. Hum. Litt. Vol. 128 245

reaction is fierce, and carbon dioxide is released in the form of gas. This gas flow is isolated into separate vials at different stages of the dissolution process. Thus the first isolated batch of the gas is identical with the first CO2 fraction, and should not be affected by contamination. Any effects of unburned limestone will appear later in the dissolution process, in later CO2 fractions.

At Torre de Palma, a total of 252 mortar samples were collected, 65 of which have been analyzed. Mortar at Palma is not unlike the non-hydraulic lime mortars from Åland, and likewise it was initially dated in two CO2 fractions. But since there was no age control from independent dating methods available for the buildings, internal consistency of the mortar dates was the only way of assessing the reliability at Torre de Palma. Therefore the strictest possible criterion was adopted for the interpretation. This protocol Ringbom et al. call Criterion I. 3 Criterion I is fulfilled when both CO2 fractions yield the same age. Thus, they demonstrate that the results are unaffected by either contamination of unburned limestone or by re-crystallization. Therefore only Criterion I samples were accepted (Fig. 2).

3 See further definition of the different criteria in Å. RingboM - J. heineMeieR - a. LindRooS - f. bRock, ‘Mortar Dating and Roman Pozzolana, results and interpretations’, in this volume.

800BC 600BC 400BC 200BC BC/AD 200AD 400AD 600AD 800AD

Baptistery, large font, second stage

Basilica, Apse 3

Maosoleum

North East Building

The Basilica, Apse 4

The Basilica, phase 2

The Olive Press

Precinct Wall

The Baptistery, earlier structure

South West House

South Field West

The Temple in East Court AAR-3933 TP 108 Cat1 1885±35BP AAR-5441 TP 186 1683±45BPAAR-5442 TP 188 1750±45BP AAR-3929 TP 069 1711±35BP AAR-10361 TP 013 1684±35BPAAR-3411 TP 201 1738±55BP AAR-5440 TP 182 1601±35BP AAR-4231-2 TP 083-2 1628±55BP AAR-3926 TP 023 1535±30BPAAR-4825 TP 143 1554±20BP AAR-5653 TP 209 1483±30BP AAR-5428 TP 045 1543±35BPAAR-5643-1 TP 178-2 1515±45BP AAR-4228 TP 036-2 1576±45BP AAR-3927 TP 025 1410±35BPAAR-3928 TP 026 1448±30BPAAR-3414 TP 206 1417±30BP AAR-4822-3 TP 138-3 1393±40BP

Torre de Palma - Chronology based on CI samples

Calibrated date

Figure 2. Calibrated results (Criterion I samples) for non-hydraulic lime mortar from Torre de Palma, Portugal.

246 LangLey et al.

Eighteen of the 65 samples analyzed fulfilled the required demands of Criterion I, and thus provided a chronology for 12 out of 21 constructions from which mortar samples were taken. Among those firmly dated are the different building stages of the Basilica’s construction. The villa urbana itself was not analyzed due to heavy secondary restorations.

Mortar dating at Torre de Palma took place at an early stage of the development of the method. In retrospect it becomes obvious that the procedure should have been different. At least three samples should have been analyzed from each structure, and more samples should have been analyzed in complete age profiles built up by four or five successive CO2 fractions.

3. paLMa MoRtaRS and ceRaMicS

In the remainder of this paper we will compare results from the 14C dating of the mortars with the well-established dates obtained from analysis of the terra sigillata and the African Red Slip (ARS) ware from three of the complexes explored (Fig. 3). The two techniques actually date different things. Analysis of the mortars can only provide the specific date at

Figure 3. Plan of the site of Torre de Palma highlighting the areas under consideration.

Comm. Hum. Litt. Vol. 128 247

which a wall was either constructed or repaired. The imported ceramics, on the other hand, provide the date of occupation of a structure or area. While one would not expect precise congruence between these two different types of dates, one could reasonably expect the ceramic chronology to suggest a beginning of occupation close to the date suggested by the mortar analysis for the construction of the building. It is not the purpose of this paper to prove or disprove the validity of the 14C mortar dating process in general but to examine the process as applied at Torre de Palma specifically and to determine the ways in which the use of both of these methods can compliment one another. This comparative analysis helps provide a greater understanding of the history of a complex than would be possible if applying either technique in isolation.

Torre de Palma is, for reasons yet to be elucidated, a site blessed with an abundance of terra sigillata and ARS ware. The study of this collection, and the site’s importance as a center of consumption, is the focus of Langley’s dissertation. Terra sigillata is a molded ceramic ware made by mass production and noted, generally, for its high grade fabric and low to high gloss engobed exterior finish and sometimes for highly decorative compositions. It is, in fact, a ware that is chronologically and geographically marked by its form, decoration, and sometimes, maker’s stamp. The fabrics that appear at Torre de Palma were produced in the Roman provinces located in modern day Italy, Southern France (South Gaulish) and Northeastern Spain (Tricio/Tritium Magallum). The predominant forms discussed in this article are vessels that served as cups (app. 150 ml), small bowls (app. 250 ml or less), medium bowls (app. 500 ml to 750 ml) and large bowls (app. 750 ml or more) that were for individual service or as central service for shared food portions. The occasional vase and cantina are also found. The predominant fabrics from the complexes discussed in this article came from various production centers radiating from the area of Tricio in the Ebro Valley of Northeastern Spain terra sigillata hispânica 4. The body of South Gaulish (gallo-romaine) fabrics, which came from the production center of La Graufesenque, near modern day Millau in the Aveyron region of France5, is represented to a lesser extent. From these select complexes at Torre de Palma, fewer than 5 specimens of Italian fabrics were present. The predominant forms and fabrics of ARS wares, or what some researchers refer to as African sigillata6, were African D, with the D1 fabric being the most frequently represented in these complexes and overall on this site. The majority of ARS-D fabrics represented at this site were produced in the northern region of Tunisia7. The methodology chosen was to assign the known circulation dates when forms were concretely identifiable, while in the case where forms were not identifiable, but the fabric was, the possible range of circulation dates for that fabric was assigned (Dgeneric, etc.). The sherds were examined subjectively and classified accordingly in order to reflect a representative number and not an underestimated or an augmented amount. This argument for MNV (minimum number of vessels) quantification is convincingly presented by

4 M. beLtRân LLoRiS, Guía de la cerámica romana, Zaragoza 1990.5 c. béMont - J.-p. Jacob (dir), ‘La terre sigillée gallo-romaine. Lieux de production du Haut Empire: implantations, produits, relations’, Documents d’Archéologie Française 6, Paris 1986.6 t. peña, www.classics.buffalo.edu, 2007.7 M. bonifay, Etudes sur la céramique romaine tardive d’Afrique (Vol. 1301), Oxford 2004.

248 LangLey et al.

Fletcher and Heyworth8 who compared three different methodologies for the quantitative analysis of ceramic sherds. This is important to note as when we turn to the information presented later in this paper regarding the MNV peaks of importation (vessels per year), an over or under estimated number of vessels should not be expected. In short, those peaks of importation for MNV’s should be a realistic number or, at least, an approximate number of vessels at any given period9. Fentress and Perkins10 introduced the basis for this methodology from field survey campaigns and the same theory has since been applied in research produced by Hawthorne11 on some 500 sherds collected from Carthage and Lepcis Magna. This work will consider the MNV in the given complexes vs. the raw sherd count in its analysis.

For the most part, the dating of various forms of terra sigillata and ARS wares is well defined. Certain sources such as J. Hayes12, A. Carandini13, J. Salamonson14 and Fulford and Peacock15 have long been considered as authoritative and even essential for recognizing and defining form typologies and their associated chronologies. Dates have been refined over the last 15 years or so. Important to this paper is new work on chronologies of African Red Slip and hispânica tardia wares. In the case of ARS wares, the work of Michel Bonifay16 and, to a lesser extent, of M. Mackensen17 and M. Ben Moussa18 are of great importance as all have worked to reassess production centers, consumption centers, and fabric designations. Bonifay has also established tighter chronologies for certain fabrics and forms. In the case of production of terra sigillata hispânica, many questions remain regarding the early production centers, which reproduced and modified the standard

8 W. fLetcheR - M. heyWoRth, ‘The Quantification of Vessel Fragments’, in c.f. gaffney (ed.), Pragmatic Archaeology Theory in Crisis? (BAR 167), Oxford 1987, 35-46.9 J. haWthoRne, ‘Vessel volume as a factor in ceramic quantification: the case of African Red Slip Ware’, in k. LockyeaR (ed.), Computer Applications and Quantitative Methods in Archaeology, 1996, Oxford [2000], 19-24.10 e. fentReSS - p. peRkinS, ‘Counting African Red Slip Ware’, Antiquités Africaines 24 (1988) 205-214.11 J. haWthoRne, Post-processual Economics; the Role of African Red Slip Wares in Mediterranean Demography, Theoretical Roman Archaeology Conference, University of Sheffield, March 1996, Oxford 1999.12 J. W. hayeS, Late Roman Pottery, London 1972.13 a. caRandini (ed.), Atlante della Forme Ceramiche. I. Ceramica fine romana nel bacino mediterraneo (medio e tardo impero), Rome 1981.14 J.W. SaLoMonSon, Études sur la Céramique Romaine d’Afrique (Archaeologische Studien Van Met Nederlands Historisch Instituut te Rome 43), 1968.15 M. fuLfoRd, Excavations at Carthage, The British Mission vol I,2: The Avenue du President Bourgiba, Salammbo: the Pottery and other Ceramic Objects from the Site, Sheffield 1984.16 bonifay 2004, cit. n. 7.17 M. MackenSen, ‘Production centres of African red slip ware (3rd-7th c.) in northern and central Tunisia: archaeological provenance and reference groups based on chemical analysis’, Journal of Roman Archaeology 15 (2002) 121-158, plate 272; and ‘Production centres of African red slip ware (3rd-7th c.) in northern and central Tunisia: archaeological provenance and reference groups based on chemical analysis’, Journal of Roman Archaeology 16 (2003) 121-158; and ‘Production centres of African red slip ware (2nd-3rd c.) in northern and central Tunisia: archaeological provenance and reference groups based on chemical analysis’, Journal of Roman Archaeology 19 (2006) 163-190.18 M. ben MouSSa, La production de sigillées Africaines (Recherches d’histoire et d’archeologie en Tunisie septentrionale et centrale 23), Barcelona 2007.

Comm. Hum. Litt. Vol. 128 249

Dragendorff forms, and the sudden deviation of forms and fabrics as represented in types such as Hispânica tardia 37t and Hispânica tardia 42. The core argument can be best summed up by the presentation of two standard opinions. In the first scenario these changes represent the end or decline and retraction of production centers. In the second there was a complete halt in the main production areas in Spain after which there was a hiatus of some 100 years. This variation in forms and decline in production quality may best be explained by a renaissance of the first- and second-century production industry during a time contemporaneous with the later ARS C and D importations. Paz Peralta’s work on the transition19, which compliments the earlier work of Mayet20, Garabito Gómez21 and Mezquiriz22, between this early and later Hispânica production, considers another period referred to as the época intermedia (intermediate period) and places most of this later production in the third through early fourth centuries. The first hypothesis, if accepted, suggests that certain forms ceased to be produced while others continued until around the end of the third century. However, if we subscribe to the ideas presented convincingly by Paz Peralta, we must consider that some forms circulated until at least the end of the fourth century. Clearly, more research into fabrics and forms at consumption centers and their associated chronologies needs to be considered and published. However, in order to include both hypotheses, this work has considered both theories of production and chronology theories - the first and former being represented by the Series 1 lines on the MNV fluctuations and the second and later represented as Series 2 (see graphs). In this study, there is very little difference in the represented peaks of importation in the complexes chosen.

4. the coMpLexeS

As mentioned above, for purposes of this preliminary work in synthesizing absolute and relative chronological information, we selected three complexes where mortar dates meet Criterion I, where the dates from CO2 fractions 1 and 2 overlap. The information gathered from the consumption of terra sigillata and ARS wares in these specific complexes is included in the discussions of specific areas that follow. Although there are many more characteristics of the ceramics which could be discussed, the forms and their associated chronologies provide the essential information needed for this work, especially the peak of importation and consumption at each complex. This peak, in theory, represents the period in which any given complex experienced its most intense activity. As mentioned above, the ceramic material does not date the construction of each complex since pottery

19 J.a. paz peRaLta, Cerámica de mesa romana de los siglos III al VI d.C. en la província de Zaragosa. (Terra sigillata hispânica tardia, african red slip ware, sigillata gálica tardia y phocaean red slip ware), Zaragoza 1991.20 f. Mayet, Les Céramiques Sigillées Hispaniques. Contribution à l’histoire économique de la Péninsule Ibérique sous l’Empire Romain (Vol. I and II), Paris 1983.21 t. gaRabito góMez, Los alfares romanos riojanos. Produccion y comercializacion (Vol. XVI), Madrid 1978.22 M.a. MezquiRiz de cataLan, La Excavacion Estratigrafica de Pompaelo. I Campaña de 1956 (Vol. VII), Pamplona 1958.

250 LangLey et al.

is an easily transportable material that could have come from any other location on site. However, a concentration of wares, over a period of time or that show a peak in representation, does suggest a more permanent and persistent activity. None of the wares from the museum collection are included in this comparative work as their proveniences were not recorded with the same rigorous archaeological field methods as those collected during the American campaigns.

5. South fieLd WeSt (coMpLex R)The area referred to as the South Field includes two ranges of rooms, South Field East (Complex S) and South Field West (Complex R), composing the southernmost part of the villa. There was no mortar found in South Field East so that section cannot be discussed here. In South Field West (SF-W), on the other hand, there were a number of mortared walls from which samples could be taken. A total of 15 were collected of which two were tested. Both of those samples fit into Criterion I (Figs. 4 and 5).

SF-W functioned as an industrial and, to a lesser extent, residential center from the third century onward. It is one of the areas of the site that give us some understanding of the life of this villa during the final years of productivity of the pars rustica. The northwestern end of this range of buildings (Southwest House B; Complex P) was partially excavated by the Portuguese in the 1950’s, but the rest of the complex of buildings was not discovered until 1995 when test pits were opened to the south of Southwest House B. Excavation continued there from 1996 until 2000. The South Field is the one area of the site that was excavated only by the American crew and where all excavated materials except fragmented imbrices and tegulae were collected and their locations recorded. This area of the site was backfilled at the end of the 2000 extended campaign and is no longer visible to visitors.

The trends for the Series 1 and Series 2 ceramic chronologies are virtually the same, although the number of MNV differs slightly. In Series 1 there is a peak during the first quarter of the third century and another peak during the first quarter of the fourth with a steady sustained rise in consumption until the second half of the fifth century. In Series 2, a peak during the first quarter of the third century levels out and emulates the behavior

Figure 4. The location of Criterion I samples in South Field West (Complex R).

Comm. Hum. Litt. Vol. 128 251

of Series 1. In the fourth century there is a very sharp peak in MNV after which it is congruent with Series 1. As can be seen (Figs. 5 and 7), both series show the same trend, that is, an initial peak of consumption during the first quarter of the third century with an escalation during the first quarter of the fourth and sustained and increased activity until the second half of the fifth.

Multiple building phases are represented in this complex as a whole. Sample TP188 (stands for Torre de Palma, mortar sample 188) was taken from a section that, based on architectural criteria, belongs to the earliest phase of construction in this area. Sample TP186, on the other hand, was taken from a wall that was clearly an addition to the original structure. One would therefore expect that TP188 would yield a date earlier than that of TP186 and that, indeed, is the case.

A comparison of the results of the mortar dates with those obtained from the ceramic analysis reveals almost complete agreement. The mortar date indicates the wall from which TP188 was taken was built in the third or early fourth century, coincidental with the first plateau in the ceramic chronology. Combining the two, the preponderance of the evidence indicates construction and intensive occupation of the area near the middle of the third century. The addition (TP186) was probably constructed in the fourth or early fifth century, when ceramic consumption was at its height. Since the consumption of imported wares is so high in the fourth and fifth centuries, the other additions to the structures, from which no samples were tested, probably also date from that period. The majority of the coins found in this area also correspond to this period of most intense occupation. So, in SF-W there is virtually complete congruence between all three chronological indicators.

Figure 5. Comparison of chronological indicators (ceramics, mortars and coins) in South Field West (Complex R).

252 LangLey et al.

6. noRtheaSt buiLding (coMpLex c)

The Northeast Building (NEB) (Fig. 6) lies approximately 80 meters north of the villa urbana, on the north side of a stream that divides the site into two parts. It was discovered and almost completely uncovered by the Portuguese and re-excavated by the University of Louisville crew during the seasons of 1999 and 2000. A previously unknown pair of walls was revealed on the east side of NEB during the re-excavation project but few artifacts were recovered there.

A midden on the south side of the building was also newly discovered in 1999-2000. Much, but not all, of the ceramic material recovered during this later excavation was actually from this midden. Since that midden is so close to NEB, but not proximate to any other buildings beside the Basilica complex, it is safe to assume the use of the midden corresponds to the occupation of NEB.

The Northeast Building, as currently visible, consists of two parts, a large courtyard with rooms on each side and a more formal building to the east with rooms symmetrically arranged around a central hall. Although it is not evident from the plan shown here (Fig. 7), the present eastern building shares at least part of the plan with an earlier building. To further complicate the interpretation, repairs to the building may have been made during the course of its life.

This complex yielded some 204 sherds of terra sigillata/ARS with a MNV of 134 with 46 identifiable forms. These vessels were consumed, from a circulation standpoint, over a period of 550-600 years. There is a low level of imported wares until the mid third century when there is a sharp rise. Consumption increases again during the last quarter of the fourth century.

Nineteen mortar samples were taken from NEB, seven of which are from opus signinum floors. Of the remaining 12, eight were taken from the same wall, one of the few containing significant amounts of mortar. Six of those 12 were tested and two of those meet Criterion I (Figs. 6 and 7).

In this complex chronological indicators do not coincide. While the coins date from the fourth century when imported wares were plentiful, the mortars suggest a date, probably near the mid sixth century, when consumption of such wares was virtually non-existent. It is not certain why there is this discrepancy. One must consider the possibility that the mortar readings are incorrect. However, there are other possible explanations. Since the wall from which the samples were taken is somewhat different in terms of mortar content from other walls in the complex it is possible these mortars represent a rebuilding or a repair of the original structure. It is also possible the building was repaired and continued

Figure 6. The location of Criterion I samples in the Northeast Building (Complex C).

Comm. Hum. Litt. Vol. 128 253

in use, perhaps with a different function that was not conducive to the use of “fancy” imported wares. For example, if the building was converted to a religious use, perhaps monastic, one would not expect imported wares to be a common feature of the table.

7. baSiLica (coMpLex b)The basilica was discovered and extensively excavated during the Portuguese campaigns (Capela, Ermida de São Domingos)23 and later, re-excavated by the American crew in the early 1980’s and revisited in the late 1990’s. Most of the burials and features were discovered during the first campaigns although the American efforts here yielded some new discoveries. Both excavations yielded only a few shards of either terra sigillata or ARS. Only a single datable shard, hispânica tardia 37t, was retrieved from this complex. That fragment dates to the late fourth-early sixth century.

The Christian basilica with its related structures is perhaps the most problematic building at Torre de Palma. At the same time, it is architecturally one of the most important. Its overall plan, with four apses along its central axis, is unique among the known corpus of Early Christian churches in Iberia and perhaps in the Early Christian world as a whole. Sorting out the dates of its various phases is therefore an important task. Unfortunately, even when freshly excavated, churches are notorious for providing relatively little ceramic evidence. Palma is no exception. In addition, there are no inscriptions, sculptures, or liturgical objects which can help provide a date for this unusual structure. Most of the

23 J. Lino de SiLva, Cadernos 1947-1964, Museu Nacional de Arqueologia, unpublished.

Figure 7. Comparison of chronological indicators (ceramics, mortars and coins) in the Northeast Building (Complex C).

254 LangLey et al.

artifacts found are from the tombs, many of which predate the building of the church. The most compelling evidence for dating the original construction of the church is a deposit of 10 coins (one of which could not be identified) deposited not beneath but within the fine white concrete of the first floor in front of the easternmost apse. These coins all date between 335 and 357 and have been identified as a builders’ deposit, probably of coins then in circulation24. While fourth-century coins are known to have continued in use in the fifth, Huffstot convincingly argues that the lack of a single later coin in this collection suggests a date of the late fourth century for the deposition. A medieval re-use of part of the building has been dated by additional coins found in related tombs. Until the mortar project began, coins provided the only non-stylistic evidence available.

Because of the importance of the church and the need to put it into proper historical context, numerous mortar samples were tested. In fact, 44 of the tested 64 (or 69%) from the site overall are from the church and the surrounding area, including three from the cemeteries. For purposes of this discussion those from the cemeteries have been eliminated, leaving 41 samples with which to work (Fig. 8). Ten of those samples meet Criterion I. The relationship between the first fractions of those ten samples, as well as to the coins and the single terra sigillata fragment may be seen in Fig. 9. These indicate a fourth-century starting date for the construction of the complex with final pre-medieval construction dating to the seventh.

The two fourth-century dates, both from the baptistery, logically belong to the first phase of the church complex and are supported by the evidence provided by the coins. The three samples (TP4, 25, and 26) from the third apse (from the east) provide a remarkably consistent seventh-century date. What about the other samples?

Twelve of the additional dated samples from the basilica (Fig. 10) are either Criterion II or Criterion III samples that can therefore be compared with the Criterion I samples either because they come from the same wall or area from which one of those samples was taken or because they are logically connected to one of them through architectural or archaeological means. Those samples are shown in Fig. 11. Two of the Criterion I samples have been omitted from that chart because there are no additional samples with which they are associated.

24 J. S. huffStot, ‘Votive (?) use of coins in fourth-century Lusitania: the builders’ deposit in the Torre de Palma basilica’, Revista Portuguesa de Arqueologia 1 (1998) 221-226.

Figure 8. Location of Criterion I samples in the Basilica (Complex B).

Comm. Hum. Litt. Vol. 128 255

The first fractions of six (50%) of the twelve comparison samples support the dates provided by samples meeting Criterion I. If one considers all 21 samples (Criterion I samples plus related, that is Criterion II and Criterion III) one finds that 72% of the first fractions are correct. So, what about the 19 dated samples that neither meet the criterion of overlapping fractions nor can be easily associated with the Criterion I samples. Must they all be discarded? The answer is a cautious no. It appears as if first fractions are more often reliable than not and therefore can provide evidence for dating, especially if they are in keeping with archaeological and the more subjective stylistic data, i.e., falling within Criterion IV.

Figure 9. Comparison of chronological indicators (mortars and coins) in the Basilica (Complex B).

Figure 10. Location of Criterion I and related samples from the Basilica (Complex B).

256 LangLey et al.

8. concLuSion

At Torre de Palma the 14C dating of mortars has proved to be valuable aid in studying structures that are otherwise difficult to date. Of course, they are best used in conjunction with other more traditional forms of dating, especially when the samples do not fit into Criterion I. Nevertheless, the other samples provide useful, though not infallible, chronological indicators. Results at Palma also reinforce the idea that the most reliable results are obtained when multiple samples from the same or related walls or areas are tested.

Figure 11. Criterion I and related samples (Criterion II) from the Basilica (Complex B).