DNA evidence shows how well Irish integrated with Vikings

Cutting-edge DNA sequencing of more than 400 Viking skeletons from across Europe and Greenland will rewrite the history books debunking our previous image of these invaders, pirates, and warriors. Some were even Irish who had assimilated with the Vikings.

Co-first author Dr. Daniel Lawson from the University of Bristol played a pivotal role in the international research that was published in 2020, led by the University of Cambridge and the University of Copenhagen.

Dr. Lawson said: “The Vikings have an image of being fierce raiders, and they certainly were.

"What was more surprising is how well they assimilated other people. Scottish and Irish people have integrated into Viking society well enough for individuals with no Scandinavian ancestry to receive a full Viking burial, in Norway and Britain.

"We studied two Orkney skeletons from Viking graves with Viking swords who share ancestry with present-day Irish and Scottish people, who could be the earliest Pictish genomes ever studied.”

The history books taught us Vikings were brutal predators who traveled by sea from Scandinavia to pillage and raid their way across Europe and beyond. Now cutting-edge DNA sequencing of more than 400 Viking skeletons from archaeological sites scattered across Europe and Greenland will rewrite the history books as it has shown. 

The key findings are:

• Skeletons from famous Viking burial sites in Scotland were actually local people who could have taken on Viking identities and were buried as Vikings.
• Many Vikings actually had brown hair, not blonde hair.
• Viking identity was not limited to people with Scandinavian genetic ancestry. The study shows the genetic history of Scandinavia was influenced by foreign genes from Asia and Southern Europe before the Viking Age.
• Early Viking Age raiding parties were an activity for locals and included close family members.
• The genetic legacy in the UK has left the population with up to six percent Viking DNA.

The six-year research project, published in Nature, debunks the modern image of Vikings.

Work from the School of Mathematics at the University of Bristol specialized in separating out very similar ancestries.

“People in Scandinavia during the Viking age were relatively similar, but we developed advanced methods to separate their ancestries," said Dr. Lawson, Senior Lecturer in Data Science.

"This showed that Norwegians predominantly went to Ireland and Iceland, whilst Danes came to England.

“But Vikings were often diverse, with ancestry from all over Scandinavia and the British Isles found in the same raiding party. The Vikings coming to Britain and Ireland were part of a wider migration spanning several centuries.”

The word Viking comes from the Scandinavian term ‘vikingr’ meaning ‘pirate’. The Viking Age generally refers to the period from A.D. 800, a few years after the earliest recorded raid, until the 1050s, a few years before the Norman Conquest of England in 1066.

The Vikings changed the political and genetic course of Europe and beyond: Cnut the Great became the King of England, Leif Eriksson is believed to have been the first European to reach North America – 500 years before Christopher Columbus - and Olaf Tryggvason is credited with taking Christianity to Norway. Many expeditions involved raiding monasteries and cities along with the coastal settlements of Europe but the goal of trading goods like fur, tusks, and seal fat were often the more pragmatic aim.

Lead author Professor Eske Willerslev, a Fellow of St John’s College at the University of Cambridge and director of the University of Copenhagen’s Lundbeck Foundation GeoGenetics Centre, said: “We didn’t know genetically what they actually looked like until now. We found genetic differences between different Viking populations within Scandinavia which shows Viking groups in the region were far more isolated than previously believed. Our research even debunks the modern image of Vikings with blonde hair as many had brown hair and were influenced by genetic influx from the outside of Scandinavia.”

The team of international academics sequenced the whole genomes of 442 mostly Viking Age men, women, children and babies from their teeth and petrous bones found in Viking cemeteries. They analysed the DNA from the remains from a boat burial in Estonia and discovered four Viking brothers died the same day. The scientists have also revealed male skeletons from a Viking burial site in Orkney, Scotland, were not actually genetically Vikings despite being buried with swords and other Viking memorabilia.

There wasn’t a word for Scandinavia during the Viking Age - that came later. But the research study shows that the Vikings from what is now Norway traveled to Ireland, Scotland, Iceland, and Greenland. The Vikings from what is now Denmark traveled to England. And Vikings from what is now Sweden went to the Baltic countries on their all-male ‘raiding parties’.

Co-first author Dr. Ashot Margaryan, Assistant Professor at the Section for Evolutionary Genomics, Globe Institute, University of Copenhagen, said: “We carried out the largest ever DNA analysis of Viking remains to explore how they fit into the genetic picture of Ancient Europeans before the Viking Age.

"The results were startling and some answer long-standing historical questions and confirm previous assumptions that lacked evidence.

“We determined that a Viking raiding party expedition included close family members as we discovered four brothers in one boat burial in Estonia who died the same day.

"The rest of the occupants of the boat were genetically similar suggesting that they all likely came from a small town or village somewhere in Sweden.”

DNA from the Viking remains was shotgun sequenced from sites in Greenland, Ukraine, The United Kingdom, Scandinavia, Poland, and Russia.

The team’s analysis also found genetically Pictish people ‘became’ Vikings without genetically mixing with Scandinavians. The Picts were Celtic-speaking people who lived in what is today eastern and northern Scotland during the Late British Iron Age and Early Medieval periods.

The Viking Age altered the political, cultural, and demographic map of Europe in ways that are still evident today in place names, surnames, and modern genetics.

Professor Søren Sindbæk, an archaeologist from Moesgaard Museum in Denmark who collaborated on the ground-breaking paper, explained: “Scandinavian diasporas established trade and settlement stretching from the American continent to the Asian steppe. They exported ideas, technologies, language, beliefs, and practices and developed new socio-political structures.

"Importantly our results show that ‘Viking’ identity was not limited to people with Scandinavian genetic ancestry.”

Assistant Professor Fernando Racimo, also a lead author based at the GeoGenetics Centre in the University of Copenhagen, stressed how valuable the dataset is for the study of complex traits and natural selection in the past. He explained: “This is the first time we can take a detailed look at the evolution of variants under natural selection in the last 2,000 years of European history.

"The Viking genomes allow us to disentangle how selection unfolded before, during and after the Viking movements across Europe, affecting genes associated with important traits like immunity, pigmentation and metabolism.

"We can also begin to infer the physical appearance of ancient Vikings and compare them to Scandinavians today.”

The genetic legacy of the Viking Age lives on today with six percent of people of the UK population predicted to have Viking DNA in their genes compared to 10 percent in Sweden.

Professor Willerslev concluded: “The results change the perception of who a Viking actually was. The history books will need to be updated.”

H/T: Bristol.ac.uk

* Originally published in October 2021. Updated in September 2023.