Migration and integration on the Baltic island of Öland in the Iron Age

This study explores a bi-isotopic approach to migration, adding δ¹⁸O values to samples with ⁸⁷Sr/⁸⁶Sr values for 109 individuals from the Iron Age (500 BCE–1050 CE) on the island of Öland, Sweden. Determining a local baseline for ⁸⁷Sr/⁸⁶Sr was complicated due to the wide range of variation in faunal samples so we divided the human values into three groups: local, non-local and undetermined. The addition of δ¹⁸O isotopes allowed identifying further non locals than the data from the ⁸⁷Sr/⁸⁶Sr alone provided. We found significant migration rates in both the Early period (500 BCE–400 CE) with 30% non-locals and in the Late (400–1050 CE), more than doubling to 68%. In both periods the non-locals appear to have diverse geographical origins. In order to study integration and migration patterns we use a bioarchaeological approach to these non cremated individuals who come from all types of contexts, i.e. not just burials. This allows discussing the cultural and social integration of non-locals. Integration is apparent in both periods and in the Late period, with a higher proportion of non-locals, there is both integration and diversity. The proportion of female non-locals suggest a mobility in both periods, especially the Late, that is relatively large. Our results of diverse non-local origins, female mobility and integration on Öland throughout the Iron Age add a new perspective, a Scandinavian multi-isotopic bioarchaeological perspective, to current discussions of Viking movement and expansion.