Explain how the concepts of nationality, multiethnic state, and nation-state contributed to the break-up of Yugoslavia.

Three federations have borne the name Yugoslavia ("Land of the South Slavs"). The Kingdom of Yugoslavia (Kraljevina Jugoslavija), officially proclaimed in 1929 and lasting until World War II, covered 95,576 square miles (247,542 square km). The postwar Socialist Federal Republic of Yugoslavia (Socijalistička Federativna Republika Jugoslavija) covered 98,766 square miles (255,804 square km) and had a population of about 24 million by 1991. In addition to Serbia and Montenegro, it included four other republics now recognized as independent states: Bosnia and Herzegovina, Croatia, North Macedonia, and Slovenia.