Diet and mobility in Byzantine Western Anatolia: carbon and nitrogen isotopic ratios and ancient DNA evidence from Barcın Höyük and Kadıkalesi Anaia

Abstract

This study presents the integrated results of stable carbon (δ13C) and nitrogen (δ15N) isotope and aDNA

analyses, conducted to examine dietary andmobility practices in twomid- to late Byzantine communities in

western Anatolia: the coastal cosmopolitan site of Kadıkalesi Anaia and the rural inland settlement of

Barcın Höyük. Isotopic data from thirty-eight individuals indicate that both populations primarily consumed terrestrial C₃-based resources. At Kadıkalesi, δ15N values show greater variability, suggesting more differentiated access to animal protein sources, whereas the rural community at BarcınHöyük exhibits isotopic homogeneity, consistent with more uniform dietary practices and an equitable access to food. Kadıkalesi also shows intra-site dietary variation by age and sex,while Barcın is again more homogeneous. At Barcın, aDNA results indicate a predominant local genetic continuity, suggesting a stable population; a single instance of external ancestry is attested by a male individual with affinities to western populations, particularly from eastern Europe, in line with historical military resettlement patterns (stratiotika ktemata). By integrating isotopic and genomic evidence, this study demonstrates how ancestry andmobility shaped dietary habits, offering insights into the interplay of urbanism, mobility, and social organization in the Byzantine period.