Economic and socio-cultural consequences of changing political rule on human and faunal diets in medieval Valencia (c. fifth–fifteenth century AD) as evidenced by stable isotopes

This paper explores the impact of changing religious political rule on subsistence within a single city through time using stable isotope analysis of human and animal bone collagen. The diet and economy of the medieval city of Valencia (Spain) are examined over a 1000-year period during successive periods of Visigothic, Muslim and Christian rule. Bulk stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) was carried out on 67 humans and 47 animals sampled from several archaeological sites dating between the fifth and fifteenth centuries AD. Terrestrial C3 resources dominated the diet in all periods. However, an increase in consumption of C4 plants (e.g. millet, sorghum) and/or marine resources is detected among individuals dating to the Islamic period. Differences in the isotopic values of humans and animals between the three periods indicate a significant dietary diversity during the Islamic phases (eleventh to thirteenth century), compared with the earlier Visigothic phase (fifth–seventh century) and the later Christian phase (fourteenth and fifteenth century). Observed diachronic changes in isotopic results provide evidence for a shift in diet and subsistence, particularly during the Muslim and later Christian periods. This is linked with change in population and economic focus. Dietary diversity among Muslim individuals is hypothesised to indicate the polyculture that was reflected in varied Islamic agricultural practices and the presence of potential migrants from elsewhere in the Islamic world.