This essay describes the piracy that took place in the Mediterranean from the time of ancient Greece to Barbary. It explains the corso, the sea war between nonstate but state-endorsed Christian and Muslim parties, with reference to the Knights of Malta and, more extensively, the Barbary corsairs. Although the essay focuses primarily on history, it also draws some conclusions about piracy and the international system today. The essay notes a prevailing assumption that contemporary piracy off Somalia and that perpetrated by the Barbary pirates is similar, but it further notes that any similarities are slight and superficial. At the same time, similarities rooted in economic, social, and political change do exist between all outbreaks of depredation at sea and the responses to them.