Anglo-Saxon origins investigated by isotopic analysis of burials from Berinsfield, Oxfordshire, UK

The early fifth century transition from Roman Britain to Anglo-Saxon England is a poorly understood period in British history. Historical narratives describe a brutal conquest by Anglo-Saxon invaders with nearly complete replacement of the indigenous population, but aspects of the archaeological record contradict this interpretation leading to competing hypotheses. Rather than replacement, a smaller group of Germanic immigrants may have settled in England as part of the social, religious, and political turmoil happening in western Europe at this time (Dark, 2000; Henig, 2002; Higham, 1992) or rapid acculturation with little contribution from Germanic immigrants may have occurred in the vacuum of Roman abandonment. As the number of Anglo-Saxon immigrants arriving in Britain is one of the focal issues of this debate, strontium and oxygen isotopic ratios, with their ability to identify immigrants in a burial population, offer a technique to test competing hypotheses. We employ oxygen and strontium isotope ratios in tooth enamel to identify the number of continental immigrants in a sample of 19 individuals from the early Anglo-Saxon cemetery at Wally Corner, Berinsfield in the Upper Thames Valley, Oxfordshire, UK. Local variation in bio-available strontium isotope ratios is established using faunal remains from the site and by sampling soils on geological formations within 8 km of the site. The oxygen isotope results show a homogeneous sample that is slightly enriched when calibrated to local meteoric water. One individual with a significantly depleted value may be a continental immigrant. Three others are strontium outliers. With only 5.3% of the sample originating from Europe, the isotopic data support the hypothesis of acculturation. In addition, the isotopic data shows no temporal patterning, although females show a statistically significant enrichment in the oxygen isotope ratio.