Widespread violence and military conflicts dominate many historical accounts of the Early Middle Ages in Europe, but archaeological evidence to corroborate such a picture has hitherto been scarce. Analysis of human remains from the Bohemian stronghold of Budeč offers a unique insight into one such event: a wave of violence that probably followed the removal of Duke Wenceslas from power by his brother Boleslav I in AD 935. A mass grave near the hillfort holds mainly male burials that show numerous injuries sustained from sword blows, testifying to the human cost of this disturbance and demonstrating the structure and reality of early medieval violence.