By Paul Rincon
BBC News Online science staff
New scientific research adds to growing evidence that the Anglo-Saxons did not replace the native population in England as history books suggest.
History books say Anglo-Saxons replaced the Britons in England
The data indicates at least some areas of eastern England absorbed very few Anglo-Saxon invaders, contrary to the view in many historical accounts.
Chemical analysis of human teeth from a Medieval cemetery in Yorkshire found few individuals of continental origin.
Details of the work are described in the scholarly journal Antiquity.
Researchers from the University of Durham and the British Geological Survey looked at different types of the elements strontium and oxygen in the teeth of 24 skeletons from an early Anglo-Saxon cemetery at West Heslerton, North Yorkshire that spans the fifth to the seventh centuries AD.
These types, or isotopes, of oxygen in local drinking water vary across Europe and locally within the British Isles.
The differences are influenced by latitude, altitude, distance from the sea and, to a lesser extent, mean annual temperature.
Invasion of ideas
This characteristic isotope composition gets set in people's teeth before they are 12 years of age, and can therefore be used by scientists to pinpoint a person's geographical origin.
Of the 24 individuals sampled, a possible four had oxygen isotope values outside the range for the British Isles. Following improvements in calibration, the group now believes only one individual was from continental Europe.
The results support the view of other researchers that the introduction of Anglo-Saxon culture and language into Britain did not occur through large-scale replacement of native populations by invading tribes.
It seems more likely that there was a small-scale immigration from continental Europe and that the existing British population adopted the customs of these outsiders as their own.
The isotopic composition of teeth can pinpoint geographical origin
"There are practices that are being adopted from continental Europe. To what extent is that a movement of people (into Britain)? Probably not that much," Dr Paul Budd of the University of Durham told BBC News Online.
But the team did find evidence for migration into the area from other parts of Britain during the period. While the isotopic composition of Bronze Age remains from West Heslerton matched local drinking water isotope compositions, the early Medieval group were more varied.
Of the 20 locals, 13 had oxygen isotope signals consistent with an origin west of the Pennines. Dr Budd puts this down to upheaval amongst the British population after the Romans withdrew their armies and administrators from the country in the fifth century AD.
"At the end of the Roman period there was a huge collapse of a centuries-long organisation, in government and in how the landscape was used. The population moves off elsewhere to exploit the landscape for agriculture."
The Anglo-Saxons supposedly began migrating into Britain en masse from the fifth century. Their culture and language has long formed the basis for English national identity.
The findings broadly agree with a large genetic survey of the British Isles published in 2003. The study, led by Professor David Goldstein of University College London, found that the genetic stamp of the Anglo-Saxons on the British Isles was weaker than expected.
Professor Goldstein attributes less than half of the paternal input in England to Anglo-Saxon migration.
"I don't think there ever was evidence for a massive population replacement. From the genetics, it's pretty clear there was not complete replacement on the paternal side in England," Professor Goldstein told BBC News Online.
"Studies like this suggest that the number of individuals that came over is small and even in burial sites that are Anglo-Saxon culturally, they're actually natives."
However, Dr Neal Bradman, also of University College London, suggested that, since the teeth of immigrants' descendents would take on the isotopic composition of the local area, it was impossible to know whether the burials were of Britons or not without conducting genetic analysis.