In the eighth century C.E., an English monk named Bede wrote the history of the island, saying Rome’s decline in about 400 C.E. opened the way to an invasion from the east. Angle, Saxon, and Jute tribes from what is today northwestern Germany and southern Denmark “came over into the island, and they began to increase so much, that they became terrible to the natives.”
But in the later 20th century, many archaeologists suspected Bede, writing centuries later, had exaggerated the invasion’s scale. Instead, they envisioned a small migration of a warrior elite, who imposed their imported culture on the existing population. Now, a sweeping genomic study, published this week in Nature, suggests Bede may have been at least partly right. New DNA samples from 494 people who died in England between 400 and 900 C.E. show they derived more than three-quarters of their ancestry from Northern Europe.
The results address a long-standing debate about whether past cultural change signals new people moving in or a largely unchanged population adopting new technologies or beliefs. With the Anglo-Saxons, the data point strongly to migration, says University of Cambridge archaeologist Catherine Hills, who was not part of the research. The new data suggest “significant movement into the British Isles … taking us back to a fairly traditional picture of what’s going on.”
When 19th century archaeologists began to dig up Anglo-Saxon houses and burials, their finds seemed to confirm the outlines of Bede’s tale. Around 450 C.E. in western England, Roman-style pottery, tools, and architecture dwindled; jewelry, swords, and houses began to resemble those found along the North Sea coast in what is today Germany and the Netherlands. Some styles evolved into spectacular forms in the new land, such as the helmets and weapons found at Sutton Hoo in eastern England.
“You can’t deny there was a big shift in material culture—Roman Britain looks very different from the Anglo-Saxon period 200 years later,” Hills says. In spite of that, “Most archaeologists have been critical of the idea of migration,” rejecting it as an overly simplistic explanation for cultural change.
But the new DNA analysis revives it. Together with previously published DNA, samples from more than 20 cemeteries along England’s eastern coast suggest a rapid, large-scale migration from Northern Europe, beginning by 450 C.E. at the latest. “Some Anglo-Saxon sites look almost 100% continental European,” says co-author Joscha Gretzinger, a geneticist at the Max Planck Institute for Evolutionary Anthropology. “The only explanation is a large amount of people coming in from the North Sea zone.”
The population shift brought huge cultural changes, some of which reverberate today. “There was a relatively dramatic period of language change,” says University of Oxford archaeologist Helena Hamerow. Celtic languages and Latin soon gave way to Old English, a Germanic language that shares vocabulary with German and Dutch. “This suggests a significant number of Germanic speakers in lowland Britain,” Hamerow says.
The Vikings who surged across the North Sea a few centuries later left fewer traces, accounting for about 6% of the genes of modern English people, compared with between 30% and 40% from the Anglo-Saxons.
That’s not to say Bede got it completely right, either. The graves don’t tell a clear story of armed conquest. Even people with little continental DNA were buried in Anglo-Saxon fashion, suggesting they willingly adopted the new culture. And the DNA shows both women and men immigrated, a finding supported by other researchers’ results.
The team also found many individuals had a mixture of DNA from continental Europe and eastern Great Britain, suggesting intermarriage and integration lasted for centuries. One high status woman in her 20s with mixed ancestry was laid to rest near modern Cambridge under a prominent mound with silvered jewelry, amber beads, and a whole cow. Such evidence suggests more complexity than simple conquest, says co-author Duncan Sayer, a University of Central Lancashire archaeologist. “We’re a million miles away from an invasion hypothesis—it’s not a bunch of blokes getting in boats with weapons and conquering territory,” he says.
Family relationships within cemeteries point to mass immigration as well. At one site, three generations of people with all Northern European DNA were buried close together. “I suspect there are families, or even small villages, getting up and moving,” Sayer says, in line with evidence in northern Germany of settlements coming to sudden ends in the fifth or sixth centuries C.E. Researchers have proposed changing climate and pressure from other groups pushed people to migrate, and that the end of Roman control opened new opportunities in England.
Traces of western British and Irish ancestry in people buried on the continent suggest a reverse migration, too, with migrants’ descendants moving back after generations in Great Britain. The results undercut the idea of Great Britain as an isolated island, upset only occasionally by invasions. “Actually, the North Sea was a highway, where people were coming and going,” Hills says. “Maybe mobility is a more normal human state than we think.”