Cranial injuries as evidence for violent conflict during the Gallinazo Phase in the Moche Valley of North Coastal Peru

•Sublethal and lethal cranial trauma present in Gallinazo remains from Cerro Oreja.•Rate of cranial trauma higher at Cerro Oreja than in other non-sacrificial EIP samples.•Cranial injuries document climate of violence during Gallinazo Phase.•Violent conflict likely contributed to emergence of hegemonic state in Moche Valley. In this study cranial injuries in human skeletal remains from the site of Cerro Oreja in the Moche Valley of north coastal Peru provide a proxy measure of violence during the Gallinazo Phase preceding the rise of the Southern Moche State and are used to assess the role that violent conflict may have played in state formation. Both healed and perimortem cranial vault fractures are present in the sample of 116 individuals from Cerro Oreja. These injuries provide evidence of both intra- and intergroup violence during the Early Intermediate Period (EIP) occupation of the site, ca. 400 BCE – AD 200. The injury rate is significantly higher than that observed in a residential sample (AD 200 – 800) from the site of Moche or in an aggregated EIP sample from the larger Andean region. While escalating violence during the Gallinazo Phase might be expected if warfare contributed to the genesis of this primary state, this was not statistically verified here. The data do suggest that a climate of violence prevailed at Cerro Oreja in the years preceding the rise of the Southern Moche State and that violent conflict likely contributed to the emergence of this hegemonic polity.