Palaeo-diets and early medieval rural societies in the basque countries based on isotopic markers of C and N (5th-11th centuries)

The study of the carbon and nitrogen isotopic markers of 113 individuals from five early and late medieval sites of the Basque Country dated from the 5th-12thcenturies, allow us to make some inferences about the social and economic transformations that took place in this period. The isotopic measures of the δ'15N show a slight decrease of the protein values among the 6th and the 8th centuries, and later an increase that can be related to the transformation of the consumption and production behaviour of the peasants. The δ13C values show that these variations do not answer to significant transformations of the supply sources, but to processes of a cultural nature. Although these background trends may be recognized in other European sectors, and especially in the UK, until now we did not have a suitable chronological resolution which allowed us to analyse these processes in detail.