Maize and Sociopolitical Complexity in the Ayacucho Valley, Peru

Stable isotope analysis of skeletal remains reveals that maize was the mainstay of diet in the Ayacucho Valley of Peru during two millennia of prehistory. One hundred and seven samples of collagen from 103 individuals have a mean δ13C value of -10.2 ± 1.5 . Samples of dental enamel from six individuals have a mean δ13C value of -3.0 ± 0.7 . Twelve accelerator mass spectrometry (AMS) radiocarbon dates from these skeletal remains indicate that they range in antiquity from ∼800 BC to AD ∼1100, a time span encompassing the Formative, Huarpa, and Wari periods. These stable isotope and AMS results represent the earliest securely dated evidence for maize as a dietary staple in the Central Andes. These findings indicate that maize agriculture was the economic foundation for the development of the Wari state.