Background: the collapse of Yugoslavia

Yugoslavia was a multi-ethnic federation of six republics (Slovenia, Croatia, Bosnia-Herzegovina, Serbia, Montenegro, Macedonia) and two autonomous provinces (Kosovo, Vojvodina). It had been held together by the communist leader Josip Broz Tito (1945-1980) and by the federal structure he built. After Tito's death, ethnic nationalism grew. The end of the Cold War weakened the federal system.

Slovenia and Croatia declared independence in June 1991. Bosnia-Herzegovina, the most ethnically mixed republic (Bosniak Muslims 44%, Serbs 31%, Croats 17%), declared independence in 1992 after a referendum that Bosnian Serbs boycotted. War immediately followed, with Bosnian Serb forces (backed by Serbia) attacking Bosniak and Croat populations. Croats and Bosniaks also fought each other at points.