Recent discoveries of rapid changes in the atmospheric 14C concentration linked to solar particle events have spurred the construction of new radiocarbon annual calibration datasets1,2,3,4,5,6,7,8,9,10,11,12,13. With these datasets, radiocarbon dating becomes relevant for urban sites, which require dates at higher resolution than previous calibration datasets could offer. Here we use a single-year radiocarbon calibration curve to anchor the archaeological stratigraphy of a Viking Age trade centre in time. We present absolutely dated evidence for artefact finds charting the expansion of long-distance trade from as far away as Arctic Norway and the Middle East, which we linked to the beginning of the Viking Age at ad 790 ± 10. The methods developed here enable human interactions and cultural, climatic and environmental changes to be compared in archaeological stratigraphies worldwide.
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In praise of archives (and an open mind)
Communications Earth & Environment Open Access 05 April 2022
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All data are available in the Article or the Supplementary Information. Additional information about the site and excavation can be found at https://projects.au.dk/northernemporium/, and additional artefact photographs can be found at http://sol.sydvestjyskemuseer.dk/ using the search term ‘SJM 3’.
All code is available in the Supplementary Information.
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We thank the excavators of the site, whose work formed the basis for this study: H. Brinch Christiansen, M. Knudsen, S. Qvistgaard and M. Søvsø from the Museum of Southwest Jutland, and S. Croix and P. Deckers from Aarhus University. The large numbers of radiocarbon dates would not have been possible without the support of the staff and PhD students of the Aarhus AMS Centre: A. Fogtmann-Schulz, C. Grosen, H. Jakobsen, M. Kanstrup, S. Kudsk, M. Sand Kalaee and A. B. Valbøl Jensen. This study was funded by the Carlsberg Foundation Semper Ardens grant no. CF16-0008 (Northern Emporium project) and the Danish National Research Foundation grant no. DNRF119 – Centre of Excellence for Urban Network Evolutions (UrbNet). Brødrene Hartmanns Fond (grant no. application A34514) and Grosserer P.L. Jørgensens Mindefond supported the tree-ring measurements.
The authors declare no competing interests.
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Extended data figures and tables
Extended Data Fig. 1 Finds relating to the manufacture of wound glass beads.
a) glass vessel cullet; b) mosaic tesserae; c) splints from batches of re-melted, coloured glass; d) production debris, including droplets; e) cane ends with plier marks; f) canes for applied trail ornaments; g) ‘Ribe type’ beads; h) ‘wasp type’ beads. Photos: Museum of Southwest Jutland. High-resolution images of all finds are available at http://sol.sydvestjyskemuseer.dk/ using the search term “SJM 3”.
Extended Data Fig. 2 Finds relating to non-ferrous metalworking.
a) crucible sherds; b) fragments of clay casting moulds; c) mould fragment with impressions of a cast brooch; d) mould fragment for Berdal-type brooches. Photos: Museum of Southwest Jutland. High-resolution images of all finds are available at http://sol.sydvestjyskemuseer.dk/ using the search term “SJM 3”.
Extended Data Fig. 3 Common types of imported beads found in Ribe.
a) small segmented ‘gold-foil’ bead; b) segmented ‘gold -foil’ bead; c) segmented colourless ‘silver-foil’ bead; d) segmented blue bead; e) segmented blue metal-foil bead; f) green faceted bead; g) mosaic eye beads; h) cut tubular beads; i) blown metal-foil beads. Photos: Museum of Southwest Jutland. High-resolution images of all finds are available at http://sol.sydvestjyskemuseer.dk/ using the search term “SJM 3”.
Extended Data Fig. 4 Common types of imports from the Rhine area.
a) fragments of Mayen basalt quern stones; b) fragment of Badorf ware pottery; c) fragment of Reliefband amphora; d) fragment of Tating ware pitcher. Photos: Museum of Southwest Jutland. High-resolution images of all finds are available at http://sol.sydvestjyskemuseer.dk/ using the search term “SJM 3”.
Extended Data Fig. 5 Common types of imports from the Scandinavian Peninsula.
a) fragments of (or blanks for) whetstones made from dark and light schist; b) casting mould made of soap stone; c) sherds of soap stone vessels. Photos: Museum of Southwest Jutland. High-resolution images of all finds are available at http://sol.sydvestjyskemuseer.dk/ using the search term “SJM 3”.
Extended Data Fig. 6 Examples of sceatta coins types.
a) Wodan/Monster (W/M) – obverse and reverse; b) Continental Runic – obverse and reverse; c) Porcupine – obverse and reverse. Photos: Museum of Southwest Jutland. High-resolution images of all finds are available at http://sol.sydvestjyskemuseer.dk/ using the search term “SJM 3”.
Methods and Results descriptions (excavation and artefact chronology; radiocarbon dating); thirteen tables detailing artefact distribution per phases on this project’s excavation (SJM 3) and on the neighbouring excavation ASR 9 Posthuset from 1990 to 1991; one table with 14C ages for all tree-ring samples; two tables with detailed information about samples for radiocarbon dating and dendrochronology, as well as 14C ages and unmodelled and modelled radiocarbon dating results of these samples, calibrated with IntCal20 and the Aarhus curve; thirteen supplementary figures, of which Figs. 1 to 6 show typical artefacts from the excavations, as can be found in the Extended Data, Fig. 7 displays a map of the study area and the neighbouring excavation ASR 9 Posthuset from 1990 to 1991, and Figs. 8–13 are related to radiocarbon analyses, calibration curves and age models.
The MATLAB code used in this study.
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Philippsen, B., Feveile, C., Olsen, J. et al. Single-year radiocarbon dating anchors Viking Age trade cycles in time. Nature 601, 392–396 (2022). https://doi.org/10.1038/s41586-021-04240-5
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