Objectives: Stable carbon and nitrogen isotope ratios (δ¹³ C and δ¹⁵ N) were used to reconstruct the history of subsistence strategies in the middle Euphrates valley, NE Syria, in six temporal subsets dating from the Early Bronze Age (c. 2300 BCE) to the Modern period (19th/20th century CE). The study aims to demonstrate that changes in political and social organization over time, for which the archaeological record suggests different goals of land use and modes of production, register through dietary patterns that are reflected in isotopic data.

Materials and methods: 173 dentin samples were taken from human individuals buried at three sites (Tell Ashara, Tell Masaikh and Gebel Mashtale) together with 15 animal bone samples. Distribution of the δ¹³ C and δ¹⁵ N values in collagen was interpreted in diachronic perspective, and with regard to lifetime shifts between childhood and adolescence.

Results: Diachronically, isotope signatures indicate a clear decrease in δ¹⁵ N values accompanied by a small shift in δ¹³ C values between the Old Babylonian (c. 1800-1600 BCE) and the Neo-Assyrian (c. 850-600 BCE) subsets. A major shift in δ¹³ C values occurred between the Early Islamic (c. 600-1200 CE) and Modern (c. 1800-1950) periods. Ontogenetic changes only occur in a few individuals, but these suggest change of residence between childhood and adolescence.

Discussion: The depletion in ¹⁵ N from the Neo-Assyrian period onwards is best explained in terms of a shift from intensive to extensive farming, triggered by the fall of regional city-states after the Old Babylonian period and the formation of large supra-regional polities in the Neo-Assyrian period and later. The enrichment in ¹³ C during the Modern period was most likely the effect of more widely utilizing the dry steppes, abundant in C₄ plants, as pasture.