The collapse of Yugoslavia
For centuries the South Slavic territories were under the control of two competing empires, the Ottomans and Hapsburgs. The Turks controlled Bosnia and Serbia, while Croatia and Slovenia was part of the Hapsburg empire, and then the Austro-Hungarian empire.
The Yugoslav nation was formed after WWI. Nevertheless, the county was dominated by the Serbs, and a significant source of tension was the Croatian request for greater sovereignty.
In 1941 Yugoslavia was fast taken over by German troops, and a severe fight happened within an oppressive Nazi-supported Croat state and defence actions, the two most significant of which were the Chetnik guerilla movement, consisting of Serbian freedom-fighters, and the Partisan communist movement, under the command of Josip Broz Tito.
After WWII, Tito’s communist party attempted to combine the six republics — Croatia, Slovenia, Serbia, Montenegro, Macedonia, and Bosnia-Herzegovina and balance the competing interests of the various ethnic groups.