Piracy holds a special place within the field of international law because of the universal jurisdiction that applies: any state may seize a pirate ship on the high seas and decide upon the penalties to be imposed, as is currently the case with Somali and West African pirates. Unlike today, piracy was the norm in pre-modern times. Maritime trade and piracy went hand in hand. At the same time, kings and emperors recruited their admirals from among pirates. This raises the question of how princes, states and cities distinguished between legal and illegal violence at sea. How did they deal with maritime conflict among themselves and among their respective subjects and citizens? This article puts maritime conflict management in a European, global and long term perspective while avoiding anachronistic and teleological approaches. Finally, it argues that pre-modern conflict management is relevant to understand maritime security in the twenty-first century.