The Scandinavians of the Viking Age were skilled navigators, fierce warriors and enterprising merchants. But the Vikings didn’t just trade goods.
A new study, carried out by researchers at Stockholm University, shows that the open society of the Viking Age left a huge mark on Scandinavia’s gene pool, which was much more diverse than previously thought.
One group in particular has shaken up the gene pool, only to mysteriously disappear again.
The Vikings preferred to have children with people from Western Europe
Researchers from Sweden and Iceland have examined the genetic material of almost 300 people who have lived in Scandinavia over the past 2,000 years. The DNA results were then compared with genes from 16,000 Scandinavians living today and more than 9,000 people whose ancestors came from other parts of Europe.
This analysis of genetic material confirmed the researchers’ suspicions that the genomes of Viking Age Scandinavians had been mixed with genes from outsiders, such as the British and Irish and people from the eastern Baltic and southern Europe, between about 750 and 1050.
But one of the more startling discoveries now is that it was primarily women who migrated to Scandinavia from Eastern Europe, and that the genes from the East quickly disappeared from the Northern DNA after the Viking Age, while the influences from the West are still present in the genes of traceable to the Scandinavians.
This led the researchers to conclude that the Vikings were more likely to have children and raise families with immigrants from the west – i.e. the British-Irish islands – and less with migrants from the east.
Another big surprise is the massiveness of the migration, especially compared to pre- and post-Viking times. The primary reference material from the pre-Viking period was DNA from skeletons from a massacre at Sandby Castle on the Swedish island of Øland around the year 450.
Supplemented with DNA from some other excavations, it became clear that the gene pool of the Iron Age Scandinavians – several centuries before the start of the Viking Age – was still very uniform. The study also shows that the DNA of the people of that time is remarkably similar to that of modern Swedes.
The researchers also found a similar genome in skeletons from the Swedish warship Kronan, which capsized and exploded off the coast of Öland in 1676. Although there is a gap of 1,200 years, the DNA of the skeletons is very similar to that of the dead at Sandby Castle, as well as the Swedes of today.
Reason for migration stop is still uncertain
Historians and archaeologists agree that the Viking Age’s varied gene pool is the result of better opportunities for sea transport, more trade and more international interaction in general.
‘During the Viking Age, the world suddenly became much bigger. If you went to the trading cities, you could meet people who were very different from you,’ archaeologist Søren Michael Sindbæk tells Historia.
However, the researchers are still not quite sure why there are so few traces of the migrants from that time several centuries after the end of the Viking Age.
According to the researchers, one explanation could be that the new arrivals were traders who returned after a short stay or monks who lived a celibate life and therefore did not pass on their genes. They may also have been slaves who were kidnapped and not allowed to have children.
Søren Sindbæk also points to another possibility. Due to the burial rituals from the Middle Ages, there are many more skeletons and therefore a greater variety of DNA material has been preserved.
We don’t know if the graves from the past we found are representative, Sindbæk points out.
But the study doesn’t just teach us more about the Iron Age and the Viking Age, adds the archaeologist. DNA analysis offers new opportunities to nuance our knowledge of the past and humanity. Thanks to better instruments, we can increasingly determine someone’s origins and history from DNA.
In this way, we can get closer to ordinary people, even those from the distant past. ‘A museum visit becomes interesting if we can meet a farmer’s son from Jutland with an English ancestor or a slave daughter from Bornholm with roots in Finland,’ says Sindbæk enthusiastically.