Variations in dietary patterns in the ancient Greek colony of Abdera: insights from isotopic evidence and Bayesian modelling

Abstract Abdera is an ancient Greek colony in northern Aegean. It exhibits a unique foundation history as it was first established in 654 BC by the Ionian city of Klazomenae and in 545 BC by the city of Teos. The first colonial endeavor failed due to harsh living conditions and conflicts with local populations. Exposed to unfamiliar challenges, the settlers faced physical strain and maladies, particularly affecting the subadults, who were deprived of proper care and nutrition during critical periods of life. After about a century, the city of Teos colonized Abdera under the pressure of the Persian attacks. The new colonial endeavor was successful, and the city managed to capitalize on its natural resources, flourishing through the centuries. This study reconstructs the diet of 109 adults and subadults from Abdera dating from the Archaic through the Roman times (654 BC–400AD) using stable isotope ratios of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) from bone collagen. Bayesian modelling was implemented to quantify the relative consumption of different food sources in Abdera and compare it with other contemporary sites. Weaning duration was estimated to investigate the nutritional and health status of infants that is believed to have affected the fitness of the population in the long run. Our results indicate that the first settlers of Abdera primarily relied mostly on C3 plants, freshwater fish and less animal protein, while marine fish and C4 plants (millet) complemented the diet. This pattern persisted over time. Bayesian modelling revealed differences in consumption patterns within the site and among other contemporary populations. The first colonization phase was characterized by prolonged weaning indicating that harsh living conditions forced mothers to rely more on breastmilk as a nutritional buffer. The sulfur analysis revealed different migration and dietary patterns in Abdera females especially during the first colonial phase. Our study highlights the significance of diet as a key factor for studying the trajectory of a settlement, and for understanding the growth, the resilience, and the cultural evolution of the ancient Greek colonies.