Social hierarchy of the Peng state in the Western Zhou Dynasty: Stable isotope analysis of animals and humans from the Hengshui Cemetery, Shanxi, China

Carbon and nitrogen stable isotope analyses were performed on the bones of seven dogs and 82 humans in the Hengshui Cemetery to reveal the distribution of food resources among different social strata of the Peng state. This study shed light on the social stratification during the Western Zhou Dynasty (c. 1046-771 BCE). The isotopic data of two Peng Bo could give the direct evidence to reveal the dietary pattern of the highest rank people in the Peng state which could be unique to discuss the whole social hierarchy of this principality. The results showed that humans and dogs mainly consumed C4-based food at the Hengshui Cemetery, although the intake of animal protein and C3 food varied significantly among the different strata. C4-based food, likely millets, and/or domestic animals fed on millet and/or millet by-products, were the main food consumed. Social stratification differences were observed in the consumption of animal protein between grave owners and sacrificed humans. Aristocracy always consumed more animal protein and C3 food than commoners. Meanwhile, sacrificed humans (SH-A) buried for the head of the Peng state, Peng Bo, consumed more animal protein and C3 food than those (SH-B) for other nobles, perhaps the former's close relationship with their masters. In addition, commoners consumed more animal protein than SH-B. Some SH-A, who had a similar dietary pattern to that of Peng Bo, might be high-ranking nobles. Differences in people's diet revealed by stable isotopes can reflect the strata of ancient societies. Peng state likely established a strict social hierarchy which ran, top to bottom: Peng Bo, nobles, SH-A, commoners, SH-B, on the dietary distribution perspective.