Yugoslavia is a new country of old peoples. Slavic tribes settled in what is now Yugoslavia during the sixth century and ruled themselves until the Ottoman Turks began their Balkan expansion in the twelfth century. After the collapse of the medieval kingdoms of Croatia, Bosnia, and Serbia, the South Slavs (južni slaveni orjugoslaveni) were ruled variously by Austrians, Hungarians, Italians, and Turks. The division between the jurisdictions of the Christian powers and the empire of the Muslim Turks marked a major cultural divide that reinforced the earlier cleavage between Catholic and Orthodox South Slavs. By the time the South Slavs were brought into a common state in 1918, they had become accustomed to thinking of themselves as Slovenes, Croats, Serbs, and Montenegrins-that is, as distinct peoples. The additional presence of certain non- Slavic peoples (Hungarians, Albanians, Germans, and Italians), together with Slavic Bulgarians and Macedonians, further complicated the picture and helped to make the so-called national question a burning issue for the interwar Kingdom of Yugoslavia. It has remained a central issue for postwar Yugoslavia.
Because Yugoslavia is a new country, ties of ethnicity have continued to exert greater hold on its people than do ties of political loyalty to the state. The interwar kingdom foundered on its misconceived denial of these differences among its Slavic peoples (treating them as members of a single "Yugoslav nation"); Yugoslavia's postwar communist regime succeeded in assuaging ethnic sensitivities not by eroding their bases but by creating ethnic republics of Slovenia, Croatia, Serbia, Macedonia, and Montenegro within the political body of Yugoslavia and conceding vast jurisdiction to these republics. Yugoslav politics in the years prior to 1989 was correspondingly shaped by a delicate balance of power among the federal units, a balance in which issues have been heavily colored by the ethnic factor.