A walrus rostrum (upper jaw bone) with tusks used in the DNA study. It is dated to 1200 – 1400 AD based on the characteristics of a runic inscription in Old Norse. It is from the collections of Musée Vert, muséum d’histoire naturelle du Mans, and may once have been part of an ecclesiastical treasury in France (catalogue number MHNLM 2004.3.53). Photo: Musées du Mans, via University of Cambridge
The Norse, or Viking colonies in Greenland had a near monopoly on medieval Western Europe’s trade in ivory but precisely overreliance on it may have led to their mysterious vanishing, an analysis of walrus DNA suggests.
Two major Norse settlements in Greenland which flourished by the mid-12th century disappeared completely by the end of the 15th century, their mysterious collapse creating a great historical riddle.
Researchers from the University of Cambridge and University of Oslo, who studied walrus DNA from various medieval ivory artifacts, suggest that the medieval ivory trade may be the answer, the University of Cambridge has announced.
The Icelandic Sagas tell the story of Erik the Red who was exiled for murder in the late 10th century, and fled to southwest Greenland to start its first Viking settlement. The Vinland sagas from Iceland also contain evidence that the Vikings reached North America.
A map showing the Viking settlements in Greenland and North America in the High Middle Ages. Map: Legal History Sources
The two major Viking colonies in Greenland, known as Eastern Settlement and Western Settlement, that developed as a result had a population in the thousands in the middle of the 12th century, with Norse Greenland even gaining its own bishop from the King of Norway.
Theories about their collapse, which left behind only abandoned Viking ruins by 1500, have ranged from climate change to unproductive farming methods.
An alternative explanation has been that the trade in ivory in medieval Western Europe, in that case walrus tusks, may have been what actually sustained the life of the Norse Greenlanders.
While numerous and various artifacts such as crucifixes and chess pieces were produced by Western European craftsmen in the Middle Ages, the source of the ivory had never been confirmed empirically.
That has now been done comprehensively for the first time in the DNA study by the University of Cambridge and the University of Oslo.
The British and Norwegian researchers have analyzed DNA from tusks and skulls, most of which were discovered on the sites of ivory workshops throughout Western Europe.
Their analysis has revealed that the Viking colonies in Greenland may have had a “near monopoly" on the supply of ivory to Western Europe for over two hundred years.
The research team has analysed walrus samples discovered in several trading centres from medieval Western Europe: Trondheim, Bergen, Oslo, Dublin, London, Schleswig and Sigtuna.
Most of the walrus tusk and bones examined in the study, which has also demonstrated an evolutionary split in the walrus, date to between 900 and 1400 AD.
The DNA analysis shows that during the last Ice Age, the Atlantic walrus split into two ancestral lines.
The “eastern" walrus line is widespread across much of the Artic, Scandinavia included, while the “western" walrus line is unique to the waters between Canada and Western Greenland.
The study has demonstrated that while the earlier walrus ivory artifacts in Western Europe were mostly from the eastern lineage, as of the 12th century, with ivory demand growing, Western Europe’s ivory supply started to be derived almost entirely from the western lineage – the walruses seemingly supplied by the Norse settlers in Greenland.
The Norse Greenlanders of the High and Late Middle Ages appear to have procured the walrus ivory through hunting but possibly also through trade with the indigenous peoples of Arctic North America.
An elaborately-carved ecclesiastical walrus ivory plaque from the early period of medieval walrus ivory trade. The plaque depicts Jesus Christ, together with St Mary and St Peter, and is believed to date from the 10th or 11th century. It was discovered in North Elmham, Norfolk, UK, in the 19th century, and is currently exhibited in the University of Cambridge’s Museum of Archaeology and Anthropology. Photo: Museum of Archaeology and Anthropology, University of Cambridge
“The results suggest that by the 1100s Greenland had become the main supplier of walrus ivory to Western Europe – a near monopoly even," says Dr. James H. Barrett, study co-author from the University of Cambridge’s Department of Archaeology.
“The change in the ivory trade coincides with the flourishing of the Norse settlements on Greenland. The populations grew and elaborate churches were constructed," he adds.
“Later Icelandic accounts suggest that in the 1120s, Greenlanders used walrus ivory to secure the right to their own bishopric from the King of Norway. Tusks were also used to pay tithes to the church," Barrett elaborates.
He points out that the period from the 11th until the 13th century was a time of demographic and economic boom in Europe.
Largely because of that, there was growing ivory demand from urban centers and the elite served by transporting commodities from increasingly distant sources.
“The demands for luxury goods produced from ivory may have helped the far-flung Norse communities in Greenland survive for centuries," Barrett notes.
“We knew from the start that analysing ancient DNA would have the potential for new historical insights, but the findings proved to be particularly spectacular," comments in turn study co-author Dr. Sanne Boessenkool of the University of Oslo.
While Barrett and his colleagues admit that their study provides less information about how the Norse colonies in Greenland ended, they emphasize that it is hard to find evidence of walrus ivory imports to Europe that date after 1400.
Walrus ivory exports from the Viking colonies in Greenland could have stalled for a variety of reasons, and it was eventually replaced by elephant ivory or mammoth ivory.
“Changing tastes could have led to a decline in the walrus ivory market of the Middle Ages," says Barrett.
Other possible causes include over-hunting leading walrus populations to abandon their coastal “haulouts"; the “Little Ice Age" – a sustained period of lower temperatures which began in the 14th century; the Black Death that ravaged Europe.
“Whatever caused the cessation of Europe’s trade in walrus ivory, it must have been significant for the end of the Norse Greenlanders," Barrett emphasizes with respect to the fate of the Viking colonies in Greenland.
“An overreliance on a single commodity, the very thing which gave the society its initial resilience, may have also contained the seeds of its vulnerability," he adds.
During Western Europe’s Romanesque art period, walrus ivory was used for exquisitely carved items such as religious artifacts, with major ivory workshops in ecclesiastical centres such as Canterbury, UK, or popular ivory games.
The Viking board game hnefatafl was often played with walrus ivory pieces, as was chess, with the famous Lewis chessmen among the most stunning examples of Norse carved ivory.
The University of Cambridge points out that walrus tusks were exported still attached to the walrus skull and snout.
This “neat protective package" was broken up at workshops for ivory removal. The study was made possible by these remains since DNA extraction from carved artefacts would be far too damaging.
One of 16 walrus rostrums (upper jaw bones) found during excavations in Bergen, Norway (catalogue number BRM708/1125, University Museum, University of Bergen). These are the remains of a “package" of walrus ivory once the tusks have been removed. Photo: Dr James H. Barrett, University of Cambridge
“Until now, there was no quantitative data to support the story about walrus ivory from Greenland. Walruses could have been hunted in the north of Russia, and perhaps even in Arctic Norway at that time. Our research now proves beyond doubt that much of the ivory traded to Europe during the Middle Ages really did come from Greenland," concludes Dr Bastiaan Star of the University of Oslo.
The DNA research into medieval walrus ivory artifacts and how their trade influenced the Viking colonies in Greenland was funded by the Leverhulme Trust, Nansenfondet and the Research Council of Norway.
Bastiaan Star, James H. Barrett, Agata T. Gondek, Sanne Boessenkool. Ancient DNA reveals the chronology of walrus ivory trade from Norse Greenland. Proceedings of the Royal Society B: Biological Sciences, 2018; 285 (1884): 20180978 DOI: 10.1098/rspb.2018.0978