This paper shows that the intensity of violence in Rwanda’s recent past can be traced back to the initial establishment of its precolonial state. Villages that were brought under centralized rule one century earlier experience a doubling of violence during the state-organized 1994 genocide. Instrumental variable estimates exploiting differences in proximity to Nyanza – an early capital – suggest these effects are causal. In other periods, when the state faced rebel attacks, with longer state presence, violence is lower. Using data from several sources, including a lab-in-the-field experiment across an abandoned historical boundary, I show that the effect of the historical state is primarily sustained by culturally transmitted norms of obedience. The persistent effect of the precolonial state interacts with government policy: Where the state developed earlier, there is more violence when the Rwandan government mobilized for mass killing and less violence when the government pursued peace.