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14C

Dating the finds contained in the cenotaph of Queen Editha

Marie-Josée Nadeau, C. Matthias Hüls, Pieter M. Grootes, Ricardo Fernandes, Bernd Kromer, Susanne Lindauer

Introduction

Queen Editha died in AD 946 at the age of 36 in Magdeburg, Germany, and was buried in the St. Maurice Monastery (possibly in the church) in Magdeburg. Historical documents indicate that, at the death of her husband Otto the Great in 973, her remains were moved together with his to a joint cenotaph in the Cathedral of Magdeburg, of which the exact location is still under debate (Kuhn 2oo9). In the course of subsequent church building and renovations on the Magdeburg Dom hill, the grave monuments for Editha and Otto were established in the so-called South Church, the predecessor of the present Cathedral, dest-royed by fire in 12o7. Consequently, her remains were probably moved several times according to the whims of history, the last time in 151o. Their whereabouts were, however, unknown for a long time until, in the course of a research excavation during the conservation-restoration of Magdeburg Cathedral, in 2oo8, her cenotaph was opened and a lead box with a latin inscription, indicating it contained the remains of Queen Editha, was found. This find initiated a multidisciplinary research project, including radiocarbon dating, to verify the validity of the inscription.

The main objective of the dating endeavour was to verify if the remains found in the cenotaph are indeed those of Queen Editha, while associa-ted material was dated to obtain information on the burial history. Of the finds described in other articles in the present issue (in this volume), dif-ferent textiles, wood, plant, insect, and skeletal remains were radiocarbon dated by accelerator mass spectrometry (AMS) in the Leibniz Labora-tory in Kiel and at the Curt-Engelhorn-Centre for Archaeometry in Mannheim. The samples and their processing are listed in tables 1–3 below.

Sample Preparation

The samples were prepared according to the methods used routinely in the Leibniz Laboratory (Grootes et al. 2oo4) and the Curt-Engelhorn-Centre for Archaeometry.

In the Leibniz Laboratory, the textile samples (Tab. 1) were first mechanically cleaned under the microscope to remove contaminants such as rootlets, fibres, and sand. The textiles were then subjected to a stepwise Soxhlet-type extraction with a sequence of organic solvents of increasing polarity to remove fatty contaminants (Bruhn et al. 2oo1). This is especially important for silk as it easily absorbs oils. In sequence, the textile fibres were extracted three times each with boiling tetrahydrofurane (THF), chloroform, petroleum-ether, acetone, and methanol and then rinsed with demineralised water. Sample material was then treated with a 1 % HCl solution, to remove carbo-nates and water/acid soluble contaminants (so-salled »fulvic acids«) derived from soil and ground water. Then, the samples were treated with a 1% NaOH solution at 6o °C to remove mobile alkali soluble contaminants, »humic acids«, that could be present if the samples had been buried in soil. A final leach with 1 % HCl was applied to the alkali residue to eliminate atmospheric CO2 dis-solved in the alkali solution. The combustion to CO2 was performed in a closed quartz tube together with CuO and silver wool at 9oo °C. The sample CO2 was reduced with H2 over an iron catalyst, and the resulting carbon/iron mixture was pressed into a pellet in a target holder for AMS measurement (Nadeau et al. 1997; Nadeau et al. 1998).

The beetle remains, of which only the hard forewings (elytra) were treated, and the oat grain were not extracted with solvents, as it is unlikely

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that they were handled with bare hands, but just subjected to the standard acid-alkali-acid cleaning procedure described above. Two wood samples received a Soxhlet and acid-alkali-acid extraction.

In the Curt-Engelhorn-Centre for Archaeome-try the textile samples were washed with isopro-panol and acetone, rinsed with demineralised water and treated with 4 % HCl (6o°), o.4 % NaOH, and 4 % HCl (6o°) solution. The beetle remains and wood samples received the standard acid-alkali-acid cleaning. The samples were combusted in an Elemental Analyser (EA) and converted to graphite using Fe as catalyst (Kromer et al. 2o12).

After extraction of the textiles, the alkali solu-tions did not show the brown coloration indicative of humic acids, which means the textiles were probably not buried in soil for a long period of time, if at all. Table 1 shows the amounts of sam-ples processed, the amount of alkali residue obtained after preparation, and the carbon content of the alkali residue, calculated from the CO2 yield upon combustion. The latter, although not a pre-cise measurement, is a good indication of the degree of mineral contaminants, such as sand and fine clay, remaining in the samples after prepa-ration. Most organic compounds have a carbon content between 4o and 6o %. Variations can also be attributed to losses caused by the strength of the chemical extraction, as some of the sample material will be dissolved selectively in the acid and alkali solutions.

In the Leibniz Laboratory two sets of bone samples were treated (Tab. 2), an initial set (KIA 4o971 and 4o972), and a second batch (KIA 41613 to 41618), treated at a later time. Bone samples were crushed into o.5–2 mm grains to facilitate demineralisation. Bone grains were first treated

with acetone to remove a possible fatty contami-nation, and rinsed with demineralised water. Then they were demineralised in ca. 1 % HCl (o.3 M) till constant pH<1, washed with H2O dem till pH>4, treated for 1 hour at room temperature with 1 % NaOH solution (o.25 M) to remove humic acids, again washed, extracted with 1 % HCl (2o °C, 1 h), and finally washed till pH>4 (Grootes et al. 2oo4). The bone collagen was dissolved overnight as gelatine in demineralised water at 85 °C and pH=3. The non-soluble fraction, which may con-tain particulate contaminants, was filtered on a o.45 µm pore silver filter (bone rest). The gelatine solution was freeze-dried, and the gelatine was combusted into CO2 (Longin 1971) and turned into graphite. In view of unexpected variations in the results of the second set of bone samples, the remaining prepared original gelatine was subjected to a Soxhlet extraction with the solvents THF through acetone, as used for the fabric sam-ples, before combustion for a second measure-ment. In addition, fresh aliquots of bone samples were cleaned with the full series of boiling sol-vents, as described above, before collagen extrac-tion. Collagen yield (as gelatine) ranged from 15.7 to 21 % of the initial bone sample. Considering that a fresh bone has a collagen content of 2o–22 %, the bones were especially well preserved. As initially the preservation status of the bones was not fully known, a larger amount of material was used for the first preparations. The second preparation, using less material, showed slightly larger collagen yields, which may be attributed to shorter demineralisation times

In the Curt-Engelhorn-Centre for Archaeome-try the bone samples were crushed to small pieces and decalcified for 6h in 4 % HCl (2o°). Gelatine

Material Sample Name Sample lab Id Weight processed (mg) Weight of Fraction (mg) Fraction Carbon Content (%)Linen fabric L1 KIA 38699 18.9 13.7 55

L2 KIA 39862 10 6.2 47

Red silk P1 KIA 39863 20.2 2.6 44

P1a KIA 40377 12.3 2.6 34

P1b KIA 40378 10.2 1.3 41

P2 KIA 39864 21.1 2.5 44

Fine silk P3 KIA 39865 15.8 4.2 47

P4 KIA 39866 15.8 3.3 63

Rough linen P5 KIA 39867 16 4.1 50

P6 KIA 39868 15.8 3.6 51

Silk with blue P7 KIA 39869 17.1 3.5 47

P8 KIA 39870 16.5 3.6 51

Brown silk P9 KIA 39871 14.8 3.5 43

P9a KIA 40379 11.8 2.9 36

P9b KIA 40380 11.2 1.7 40

P10 KIA 39872 17.3 3.6 38

Insect remains K1 KIA 41318 13.6 5.8 59

Oat grain G1 KIA 41319 2.8 0.42 57

Wood, Oak MDS-232.3 KIA 47444 57.3 5.1 42

Wood, Oak MDS-691.3 KIA 47445 13.4 4.3 48

Tab. 1 Processing data for the textiles, insect remains, and oat grain in the Leibniz Laboratory: amounts processed, amounts of alkali residue obtained, and its

carbon content.

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was extracted at 6o° and ph3. The solution was filtered in an EZEE filter (ca. 6o µm) and the hig-her molecular weight fraction (MW>3okD) was obtained using ultrafiltration (Tab. 3). The gelatine solution was freeze-dried and combusted into CO2 in sealed quartz tubes. The CO2 was converted to graphite as described above.

The measurements

The samples were measured at the Leibniz-Laboratory for Radiometric Dating and Isotope Research in Kiel, and at the Curt-Engelhorn-Centre for Archaeometry in Mannheim, Germany.

The Leibniz 3 MV HVE Tandetron AMS system (Nadeau et al. 1997) produces a negative ion beam from graphitic iron targets by bombardment with cesium ions. The ions are accelerated from -35 kV to earth and pass a separator/recombinator system, where all masses except 12, 13, and 14 are elimi-nated, and the mass-12 beam is mechanically attenuated by a factor 1oo. The recombined ions of 3 masses are accelerated to the +2.5 MV termi-nal, where collisions with argon atoms in the stripper canal remove electrons from the ions and destroy molecular ions. The positive carbon ions are accelerated back to ground potential and 12,13,14C+3 are selected by a 11o° magnet to fall into

a 12C and a 13C Faraday cup and pass through a further electrostatic deflector and a 9o° magnet into the 14C detector. The simultaneous measure-ment of the two ion beam currents 12C+3 and 13C+3 and of the particle flux 14C+3 yields under stan-dard operating conditions the isotopic abundance ratios 14C/12C and 13C/12C of a 1 mg C target with a precision of about o.3 % in less than 1h (Nadeau et al. 1997; Nadeau et al. 1998). Comparison of the measured isotopic abundance ratios of the sample with those obtained for oxalic acid (OxII) modern standard and blank targets, measured interspersed with the unknown samples, provides the 14C concentration of the sample. The conven-tional 14C age is calculated according to Stuiver and Polach (1977) with a δ13C correction for iso-topic fractionation based on the 13C /12C ratio measured by the Leibniz Laboratory AMS-system simultaneously with the 14C /12C ratio. This δ13C includes the effects of fractionation during gra-phitization and in the AMS-system and, therefore, cannot be compared with δ13C values obtained per mass spectrometer on CO2. The measuring uncertainty (standard deviation σ) is based on both the counting statistics of the 14C measure-ment and the variability of the interval results that, together, make up one measurement. The larger of the two is adopted as measurement

Sample Id Sample name amount Collagen Collagen Collagen C amount of bone processed (mg) weight (mg) yield (%) content (%) rest (mg)

Original preparationKIA 40971 Befund 7230; Grave 222;

Rib; bone 533 300 55.51 18.5 50.1 0.14

KIA 40972 Befund 7230; Grave 222;

3. Metacarpale right; bone 519 300 50.18 16.7 48.2 0.22

KIA 41613 KMD 915 370 64.66 17.5 49.8 0.06

KIA 41614 KMD 916 270 48.94 18.1 52.4 0.19

KIA 41615 KMD 917 250 39.32 15.7 47.5 0.11

KIA 41616 KMD 918 270 48.49 18.0 47.6 0.21

KIA 41617 KMD 919 259 44.04 17.0 47.1 0.28

KIA 41618 KMD 920 173 31.59 18.3 47.4 0.34

Collagen cleaned with Soxhlet extractionKIA 41613 KMD 915 370 as above as above 49.2 as above

KIA 41614 KMD 916 270 as above as above 49.2 as above

KIA 41615 KMD 917 250 as above as above 52.0 as above

KIA 41616 KMD 918 270 as above as above 50.9 as above

KIA 41617 KMD 919 259 as above as above 49.9 as above

KIA 41618 KMD 920 173 as above as above 49.1 as above

Second preparation on bone material cleaned with Soxhlet extractionKIA 41613 KMD 915 122 22.56 18.5 46.7 0.04

KIA 41614 KMD 916 114 24.41 21.4 47.8 0

KIA 41615 KMD 917 118 21.42 18.2 47.6 0.14

KIA 41616 KMD 918 120 23.57 19.6 47.9 0.2

KIA 41617 KMD 919 113 21.18 18.7 44.7 0.11

KIA 41618 KMD 920 111 23.34 21.0 47.5 0.14

Tab. 2 Bone samples and their collagen extraction in the Leib-niz Laboratory. amount of bone processed, amount and percen-tage of collagen (gelatine) ob-tained, carbon concentration of the collagen fraction, and amount of bone rest obtained.

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uncertainty. To this is added the uncertainty connected with the subtraction of the »blank«. The quoted 1σ uncertainty is thus the best esti-mate for the full measurement and not only based on counting statistics.

At the Curt-Engelhorn-Centre for Archaeome-try samples were measured with a MICADAS AMS system. This is a compact 2oo kV system described in Synal et al. (1997) and Wacker et al. (2o1o). Performance of the system in the first year at Mannheim is described in Kromer et al. (2o12).

The results

The textile, wood, beetle, and oat grain samples

The 14C results of the textiles, wood, beetle remains, and oat grain are listed in Table 4. Multiple samples of each of the textiles were submitted to evaluate the reproducibility of the results.

14C ages are reported rounded to 5 or 0

The agreement between duplicate measurements of the same fabric measured in one laboratory is generally very good; for the linen fabric, fine silk, rough linen, and silk with blue within one mea-surement standard deviation. The four samples

of the brown silk agree within 1.1 standard devi-ation. Only for the red silk the spread of the four measurements exceeds twice the standard devi-ation (KIA 39863-39864 age difference 85±39 years, ~2.2 σ). The close agreement of the other three results suggests KIA 39863 is a statistical outlier. The measured 14C concentrations of the fabrics differ much more and indicate real age differences. Real age differences are, however, also observed between the results obtained for samples of the same measured in Kiel and in Mannheim. For the silk-with-blue fabric the Mannheim date is 3o years older, which is stati-stically not significant; for the four other samples the difference is 8o years. Both sets of ages are within the realm of historical possibilities, but give different attributions. For lack of archaeolo-gical / historical information both scenarios will be discussed and tests are planned to resolve the cause of the discrepancies. Two samples of oak wood dated in both laboratories showed no stati-stically significant age differences (o.1σ for MDS-691 and o.8σ for MDS232).

To relate measured 14C ages to historical events, they need to be converted into calendar ages (cali-brated). This is done using a database of atmosphe-ric 14C concentrations in the past, constructed by 14C measurements of wood samples of which the calendar age was known by tree ring counting. Figure 1 shows this calibration relation for the last 15oo years. The atmospheric 14C concentration during this period was not constant and, thus, the symmetrical age probability distribution around the measured 14C age translates into a frequently irregular mountainscape of calendar age probabi-lities, which most often complicates the precise identification of historical events.

The calibration of the results in Table 4, calcu-lated using OxCal 4.o and the IntCalo4 data set (Reimer et al. 2oo4), is shown in the figures 2–7. As can also be seen in Table 4, the Kiel replicates of each sample agree very well with each other, five within one sigma. Only the red silk sample KIA 39863 deviates by 2.2 sigma, which is the reason this fabric was resampled and redated. The function R_Combine is used to obtain a single, more precise, result for each fabric, by grouping the multiple (2–4) individual results of each sample (Bronk Ramsey 1995; Bronk Ramsey 1998). The combined result is used in the subsequent comparison between different sample materials.

MaMS Sample Name Code amount Collagen Collagen Collagen Processed (mg) Weight (mg) Yield % reat (mg)11089 MMD 921 1 1208 143.2 11.9 134.3

11090 MMd 922 2 893 139.9 15.7 130.8

11092 MMD 924 4 1320 204.1 15.5 196.1

11093 MMd 925 5 1180 94.6 8.0 84.7

Tab. 3 Bone samples and their collagen extraction in the Curt-engelhorn-Centre for archaeo-

metry. amount of bone pro-cessed, amount and percentage of collagen (gelatine) obtained,

and amount of bone rest obtained.

Fig. 1 radiocarbon calibration curve 0–2000 yr BP from

IntCal04/IntCal09.

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Material Sample Id Sample name 14C content radiocarbon age δ13C (pMC) (years BP)* (V-PdB, ‰)

Linen fabric KIA 38699 L1 94.76±0.24 435±20 -25.9±0.4

KIA 39862 L2 94.54±0.37 450±30 -25.1±0.1

Red silk KIA 39863 P1 88.17±0.29 1010±25 -21.8±0.2

KIA 40377 P1a 87.47±0.28 1075±25 -23 used

KIA 40378 P1b 87.25±0.39 1095±35 -23 used

KIA 39864 P2 87.27±0.29 1095±30 -19.7±0.2

MAMS 11241 M4 1170±25 -26.9

Fine silk KIA 39865 P3 88.46±0.29 985±25 -23.0±0.2

KIA 39866 P4 88.43±0.21 990±20 -21.0±0.3

MAMS 11238 M1 1065±25 -29.1

Rough Linen KIA 39867 P5 89.93±0.31 855±30 -29.5±0.3

KIA 39868 P6 89.90±0.27 855±25 -28.5±0.2

MAMS 11242 M5 940±25 -29.7

Silk with blue KIA 39869 P7 89.74±0.23 870±20 -22.7±0.2

KIA 39870 P8 89.40±0.27 900±25 -23.2±0.3

MAMS 11239 M2 915±25 -27.0

Brown silk KIA 39871 P9 87.90±0.27 1035±25 -22.6±0.2

KIA 40379 P9a 87.58±0.33 1065±30 -23 used

KIA 40380 P9b 88.13±0.38 1015±35 -23 used

KIA 39872 P10 87.87±0.30 1040±25 -20.1±0.2

MAMS 11240 M3 1120±30 -29.7

Insect remains KIA 41318 K1 94.23±0.22 475±20 -22.9±0.1

MAMS 14178 M11 980±25 -32.4

Oat grain KIA 41319 G1 87.41±0.73 1080±65 -27.1±0.2

Oakwood KIA 47445 MDS-691-3 88.91±0.27 945±25 -23.0±0.2

MAMS 14173 M6 940±20 -25.6

Juniperwood MAMS 14174 MDS-874 M7 860±20 -24.9

Hazelwood MAMS 14175 M8 1060±20 -26.0

Oakwood KIA 47444 MDS-232-3 87.79±0.29 1045±25 -23.1±0.1

MAMS 14176 M9 1080±20 -26.5

charred MAMS 14177 MDS-863 M10 1320±20 -31,6

Tab. 4 14C results of the texti-les, wood, insect remains, and oat grain.

Fig. 2 Calibrated results of the linen samples, calculated using oxCal 4.0.

Fig. 3 Calibrated results of the red silk calculated using oxCal 4.0.

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Sample Id Sample name 14C content radiocarbon δ13C (pMC) age (years BP)* (PdB-V, ‰)

KielOriginal SamplesKIA 40971 Befund 7230; Grave 222; Rib; bone 533 84.68±0.23 1335±20 -19.4±0.1

KIA 40972 Befund 7230; Grave 222; 3. Metacarp. r.; bone 519 85.38±0.22 1270±20 -18.9±0.1

Collagen fraction without solvents (not reliable)KIA 41613 KMD 915 87.73±0.26 1050±25 -20.8±0.1

KIA 41614 KMD 916 86.00±0.25 1210±25 -19.4±0.1

KIA 41615 KMD 917 86.98±0.26 1120±25 -19.3±0.1

KIA 41616 KMD 918 88.63±0.35 970±30 -21.3±0.2

KIA 41617 KMD 919 86.56±0.23 1160±20 -20.5±0.1

KIA 41618 KMD 920 85.42±0.26 1265±25 -17.2±0.1

Collagen preparation cleaned with solventsKIA 41613 KMD 915 86.26±0.28 1185±25 -21.3±0.3

KIA 41614 KMD 916 85.26±0.30 1280±30 -19.5±0.2

KIA 41615 KMD 917 85.92±0.32 1220±30 -20.5±0.2

KIA 41616 KMD 918 85.57±0.26 1250±25 -19.3±0.2

KIA 41617 KMD 919 84.89±0.22 1315±20 -19.6±0.2

KIA 41618 KMD 920 84.41±0.24 1360±25 -17.2±0.3

Collagen extracted after soxhlet type treatment of the bone sampleKIA 41613 KMD 915 85.23±0.40 1285±40 -19.7±0.4

KIA 41614 KMD 916 85.37±0.27 1270±25 -19.7±0.1

KIA 41615 KMD 917 85.66±0.39 1245±35 -18

KIA 41616 KMD 918 84.59±0.28 1345±25 -18.4±0.2

KIA 41617 KMD 919 84.55±0.27 1350±25 -19.1±0.1

KIA 41618 KMD920 85.01±0.29 1305±25 -20.0±0.1

Mannheim

MAMS 11089 MMD 921 86.3±0.51 1185±50 -22.3

MAMS 11090 MMD 922 86.2±0.25 1190±25 -21.6

MAMS 11092 MMD 924 85.9±0.25 1215±25 -23.2

MAMS 11093 MMD 925 85.7±0.25 1240±25 -24.9

* 14C ages are reported rounded to 5 or 0

The bone samples

Results of the bone samples, all submitted without clear attribution, are listed in Table 5 below. The ages of the two original samples KIA 4o971 and 4o972 differed by only 65 14C years, yet at 2.2 sigma this difference is statistically significant. Since the results were unexpectedly old, indicating a 7th or 8th century origin (Fig. 8), a set of blind samples was submitted both to Kiel and Mann-heim. The results obtained for this set by the Leibniz Laboratory showed a large age spread of almost 4oo±4o years, ~7.6 σ, with ages generally still older than expected for Queen Editha. After consultation, it was decided that the scatter in the results could indicate incomplete removal of contaminants and to test this by applying organic solvent extraction to both the remaining prepared

gelatine and the original bone sample to remove potential non-polar contaminants. The cleaned gelatine gave more consistent, older results, on average 85.4 pMC, (spread 1.25 pMC, ~115 yr), similar to the original two measurements (average 85.o pMC). The results of the new collagen extrac-tion, performed on bone material that was first Soxhlet-cleaned with the sequence of boiling organic solvents as described for the textile sam-ples, gave an average of 85.1 pMC (spread 1.11 pMC, ~1o5 yr), and statistically agreed with those of the cleaned gelatine and the original results. Although the exact cause of the first deviant results (average 86.9 pMC, range 88.6 to 85.4 pMC) could not be identified, we suspect that hydrophobic contami-nants, including material younger than the sam-ples themselves, remained in the collagen of the second set of samples. At this point, we cannot

Tab. 5 14C results of the bone samples.

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Fig. 4 Calibrated results of the fine silk calculated using oxCal 4.0.

Fig. 5 Calibrated results of the rough linen calculated using oxCal 4.0.

Fig. 6 Calibrated results of the silk with blue calculated using oxCal 4.0.

Fig. 7 Calibrated results of the brown silk calculated using oxCal 4.0.

identify how, when, nor where, this contamination occurred.

The results of the Curt-Engelhorn-Centre were internally consistent with an average 14C concen-tration of 86.o pMC and a spread of o.6 pMC (55 yr). Although these results are significantly younger than those of the Leibniz Laboratory, they still place the bones in the 8th or 9th Century with a low probability in the 1oth Century for MAMS 11o89 and 11o9o. The consistently old ages may be attributable to fish consumption and a resulting fresh water reservoir effect, as discussed below. The cause(s) for the age offset between the Leibniz Laboratory and the Curt-Engelhorn-Centre, this time with older ages in Kiel, will be further inves-tigated.

discussion

The results of the non-bone samples are partly younger than the death of Queen Editha, indica-ting that they may date from reburials of her remains and, thus, document the history of the Church in which she was buried. The results from the bone samples are significantly older than the death of Queen Editha, and could bring doubt to the attribution. Yet, discrepancies between histo-rical date of death and bone radiocarbon date are not uncommon. Lanting and van der Plicht (1998) reported even larger age offsets for historical medieval persons, the Counts of Holland and Belgian bishops (Tab. 6), which they attributed to reservoir effects associated with a fish diet.

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reservoir effect

The underlying assumption of radiocarbon dating is that the 14C level in the measured sample, when corrected for fractionation (Stuiver / Polach 1977), originally equalled that of the contemporaneous atmosphere. This assumption is generally valid for terrestrial material, as atmospheric 14C is well mixed and has a short residence time when com-pared to its half life (Levin et al. 198o; Levin /Hesshaimer 2ooo). Aquatic reservoirs are, howe-

ver, often 14C depleted when compared with the atmospheric reservoir and are said to have a reservoir age. This reservoir age is defined as the radiocarbon age offset between the 14C content of a specific aquatic reservoir and that of the atmosphere. The mechanisms underlying reser-voir effects are varied. An average marine reser-voir effect of ca. 4oo years for the global surface ocean (Reimer et al. 2oo9) reflects the long resi-dence time of carbon in the deep ocean and the exchange between the deep ocean and the ocean surface layer. The reservoir age needs to be cor-rected for local variations in this exchange when necessary. Freshwater reservoir ages reflect the influence of old groundwater, carbonates, and/or organics. These present a large local variability, and may cause much larger 14C age offsets than marine reservoirs, often of several thousands of years (e. g. Geyh et al. 1998; Geyh 2ooo; Hall /Henderson 2oo1; Fischer / Heinemeier 2oo3; Zhou et al. 2oo9; Ascough et al. 2o1o), without telltale deviations in the abundance ratio 13C/12C.

Radiocarbon ages of bivalve meat and shell of specimen, collected live from the Kiel Fjord (Bal-tic Sea). Lake Rosenfeld (near Kiel), and the Weiße Elster river in 2o11, are listed in Table 7. The apparent ages of meat and shell document the potential for large reservoir effects in Middle Germany (Tab. 7; Fernandes et al. 2o12). Archa-eological bovine bone and bivalve shells collected from the prehistoric site of Zauschwitz (Tab. 8), in the immediate vicinity of the Weiße Elster, show a radiocarbon age difference of nearly 18oo years, a value similar to that observed in modern specimen (Tab. 7) This indicates that this may be a general problem, to be reckoned with for this region through different historical periods.

The aquatic 14C deficiency can be transferred to humans through the food chain. People, who

Location Individual date of death date of death human age offset (yr ad) translated in 14C age (14C yr) 14C age (yr BP) (yr BP)

The Netherlands Floris I 1061 910 1020±50 110±50

The Netherlands Simon 1147 900 1360±50 460±50

The Netherlands Dirk VI 1157 920 1250±30 330±30

The Netherlands Hadewig 1167 910 1105±45 195±45

The Netherlands Willem I 1222 850 1215±50 365±50

The Netherlands Floris IV 1234 830 1180±25 350±25

The Netherlands Ada 1257 800 1075±35 275±35

The Netherlands Floris V 1296 640 995±60 355±60

The Netherlands Thibald 1160 920 1065±20 145±20

Belgium Domitianus ca. 560 ca. 1530 1560±50 30±50

Belgium Rombout 775 1250 1390±50 140±50

Belgium Mengoldus 892 1180 1390±70 210±70

Belgium Gerlach 1165 920 1160±30 240±30

Belgium Adelbert ca. 750 ca. 1280 1450±55 170±55

Tab. 6 Medieval reservoir ages (Lanting / van der Plicht 1998).

Fig. 8 Calibrated results of the bone samples calculated

using oxCal 4.1.

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Lab code Lab code Meat con- Meat Shell con- Shell(meat) (shell) ventional age apparent age ventional age apparent age (yr BP) (yr BP) (yr BP) (yr BP)

Kiel Fjord 2011 Mytilus edulis

KIA 44379 KIA 44383 290±30 610±30 350±40 670±40

KIA 44380 KIA 44384 260±30 580±30 200±20 520±20

KIA 44381 KIA 44385 280±30 600±30 275±20 595±20

KIA 44382 KIA 44386 315±25 635±25 300±30 620±30

Weiße Elster River 2009 Anodonta anatina

KIA 40107-1 KIA 40107-1 1140±20 1460±20 1495±20 1815±20

KIA 40107-2 KIA 40107-2 1010±20 1330±20 1195±20 1515±20

Lake Rosenfeld 2010 Unio tumidus

KIA 44405 KIA 44404 575±20 895±20 410±30 730±30

Tab. 7 radiocarbon (14C) results for marine and fresh- water bivalve meat and shell, collected live in 2o11 from different german sites (Kiel Fjord, Weiße elster river, and Lake rosenfeld; Fernandes et al. submitted).

consumed a significant quantity of protein from aquatic sources will show a too old radiocarbon date, attributable to this reservoir effect. Medieval populations are an historical example for which a reservoir effect is to be expected. Due to religious fasting rules, it has been estimated that medieval populations were proscribed the consumption of meat for nearly half the days of the year (Müldner /Richards 2oo5).

The average 14C concentration determined for the cleaned bone samples is approximately 85.1 pMC for the Leibniz Laboratory and 86.o pMC for the Curt-Engelhorn-Centre (Tab. 5), while a concentration of 87.o pMC is to be expected for organic material from the time of Editha’s death without any reservoir effect (Reimer et al. 2oo9; compare also with results for brown and red silk, Tab. 4). This suggests collagen with originally 97.8 and 98.9 % of the atmosphere 14C concentration of the time (depressed in 14C by 1.8 %), respec-tively, that is an apparent age of 18o and 9o 14C years at time of death, respectively. Considering the slow turnover rate of bone collagen in adults, the mean collagen age at the time of Queen Editha’s death may have been 1o to 15 years, which would leave a true reservoir effect of 17o, respec-tively 8o years. If this were to be the result of the consumption of marine fish with a mean reservoir age of 4oo years (95.1 % of atmospheric 14C), it would imply that 45 %, respectively 22 % of the collagen carbon had to be from fish. Although this is not impossible, considering medieval fas-ting rules, it is quite high. For inland locations, like the Magdeburg region, a freshwater diet component is more probable, which, considering the high freshwater reservoir ages observed, reduces the required aquatic contribution to the diet. For fish and mussels with a 14oo years reser-voir age, as documented for the mussel meat from the Weiße Elster (Tab. 7), the 14C concentration is only 84 % of that of the atmosphere and the required aquatic protein contribution to the col-

lagen carbon is lowered to 14 and 7 %, respectively. Since dietary routing studies indicate that under normal conditions ca. 75 % of the collagen carbon is contributed by proteins and the remainder by energy nutrients (carbohydrates, lipids; Fernandes et al. 2o12), only 18 and 9 %, respectively, of the protein intake would have to come from freshwa-ter aquatic sources to lead to the bone ages obser-ved. This puts no restriction on the energy nutri-ents and is as a diet for Queen Editha quite plausible. In this context, the old bone dates obtained are not unexpected.

Summary

The combined dating results of the contents of the lead box, obtained so far, are shown in Figure 9. They present the following picture:

The collagen of several different bones contains less 14C than can be expected for a plant sample from AD 946. Thus, the 14C dates cannot confirm that the bones are indeed those of Queen Editha. Yet, considering the excellent condition of the teeth, the heavy fish consumption resulting from the medieval religious fasting rules, and the high reservoir ages observed in present day and exca-vated mussel shells from middle Germany, the obtained 14C ages fit what may be expected for Queen Editha.

The, as yet unresolved, offset between the results obtained for the fabrics in Kiel and Mann-heim leads to two different scenarios.

The Kiel results range from Editha’s death to the preparations for the 151o reburial:

The single oat grain largely dissolved during chemical cleaning and, consequently, the final target contained only o.24 mg C. For such a small sample the blank correction is relatively large and its uncertainty significantly increases the overall measuring uncertainty. Thus, although the 14C age of the oat grain is consistent with a AD 946 growing season, its calibrated range stretches

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from about AD 9oo to AD 1o4o and can thus also fit later reburials. The oat grain and the soil may belong to an original earth burial.

The combined red silk results post date Queen Edithas death and suggest this silk may be con-nected with a reburial after Otto’s death in AD 973, or with later reburial activities in the first half of the 11th century. Figure 3 illustrates how multiple measurements can reduce the measure-ment uncertainty and the effect of the varying atmospheric 14C level documented in the calibra-tion curve (Fig. 2). KIA 39863-P1, which dated 65 to 85 years younger than the other three samples, narrows the combined probable age range of this sample mostly to 97o to 1o2o AD, while the others include Queen Editha’s death plus a large part of the 1oth century. Yet, an early 1oth century origin for this silk is also possible, and thus it may have been part of Editha’s original burial.

The brown silk gave a statistically highly con-sistent set of ages and post dates Otto’s death. Its calibrated age range corresponds with records of building and reburial activities in a precursor of the present Dom by Archbishops Tagino, Gero, and Hunfried (AD 1oo4–1o51; Kuhn 2oo9). The

oakwood KIA 47444 also dates to this period. The calibrated age range of the oakwood sample KIA 47445 also covers this period, but most of it is in the second half of the 11th and the first half of the 12th century, a period for which no records are available.

Two highly consistent ages for the fine silk place its origin around AD 1o5o, near the end of this phase. However, due to the fluctuations in atmospheric 14C concentration, the early part of the 12th century cannot be completely excluded. The dates agree well with dates KIA 39o81 and 39o82 for charcoal on a pre-AD 12o7 floor, found during the excavations below the present floor of the Dom (Kuhn 2oo9a).

The silk with blue yielded two precise ages, differing by less than one standard deviation. Yet, one of these has a calibrated age interval reaching from ca. AD 1o5o to AD 122o and is thus incon-clusive. The other, slightly younger date, suggests an origin close to the 12o7 Dom fire, just like the two dates for the rough linen.

The two dates for the linen fabric, in which the remains were deposited in the lead box, are sta-tistically consistent and place the origin of the fabric around AD 1445. They differ not statistically significant from the date obtained for one of the many strawberry seed beetles found in it. This suggests, Queen Editha was taken from the sar-cophagus and grave monument, constructed for her after the 12o7 fire, by the middle of the 15th century, several decades before the completion of the restauration and the inauguration of her new monument in AD 151o.

The Mannheim results are older and give a slightly different scenario:

The age range of the red silk lies mostly in the 9th century, while that of the fine and the brown silk covers the 1oth century and Editha’s death. All three may thus have been part of Editha’s original burial, or of one of the early reburials connected with Otto’s death and the activities of Archbishops Tagino, Gero, and Hunfried (AD 1oo4–1o51; Kuhn 2oo9). The oak wood of MAMS 14176 also belongs to this phase.

The hazelwood postdates Otto’s death and documents activities of the Archbishops of the early 11th century. The oakwood MAMS 14173 as well as the rough linen and the silk with blue fabric could also come from this period, but have most of their calibrated age range in the second half of the 11th and the first half of the 12th cen-tury, a period for which no records are available. Interestingly, the beetle MAMS 14178 also dates

Terrestrial sample Conventional age aquatic sample Conventional age Shell apparentCollagen (bovine bone) (14C yr BP) Mollusc shell (14C yr BP) age (14C yr)

KIA 41496 4460±40 BP KIA 41497 6225±45 BP 1765±60

Tab. 8 Zauschwitz: Fresh water reservoir age from offerings in

Funnelbeaker burial pit

Fig. 9 Calibrated results of all the samples submitted for radio-

carbon dating. Multiple results of the same material are com-bined using oxCal 4.0. (Bronk ramsey 1995; Bronk ramsey 1998). The red lines indicate Queen editha’s death in 946 ad, otto the great’s death in 973, the fire that, according

to historical sources, destroyed the cathedral in 1207, and the

date of the inscription on the lead box, 1510.

daT IN g T h e F IN d S C o N Ta IN e d IN T h e Ce N o Ta Ph o F Q u e e N e d IT h a

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from this period. The age difference with the beetle dated in Kiel, 58o±32 years, is much larger than the fairly consistent age offset observed for the other samples and indicates, not surprisingly, that not all of the beetles entered the burial assemblage at the last opening.

The age of the juniper wood indicates it must have been introduced at reburial after the 12o7 fire, while the charcoal date MAMS 14177 seems unconnected with activities concerning Editha.

The dating of the suite of finds from the lead box thus gives a picture, or rather pictures, con-sistent with what is known about Queen Editha

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