Yugoslavia was a state concept among the South Slavic intelligentsia and later popular masses from the 19th to early 20th centuries that culminated in its realization after the 1918 collapse of Austria-Hungary at the end of World War I and the formation of the Kingdom of Serbs, Croats and Slovenes. However, from as early as 1922 onward, the kingdom was better known colloquially as Yugoslavia (or similar variants); in 1929 the name was made official when the country was formally renamed the "Kingdom of Yugoslavia".
The creation of Yugoslavia has been described as expansionist and irredentist in its approach to foreign policy, and federalist in its approach to politics, with power centralised in the Serb-dominated government. Despite the idea of Yugoslavism having promoted equality among the South Slavic ethnic groups, the new Yugoslav state was ruled by the Serbian Karađorđević dynasty that sought to implement pro-Serb policies throughout the country, leaving minority groups like Croatians and Bosniaks (Bosnian Muslims) not feeling represented in the new government. This led to the formation of opposition parties that became identified with particular ethnic groups within the country. Similarly, the concept of Yugoslavism became associated with the idea of a South Slavic nation dominated by Serbs; and in some instances, forced cultural assimilation policies introduced by the Serb-led Yugoslav government. However, the creation of Yugoslavia remained popular even among non-Serbs, as it was seen as a means of unification for South Slavs to protect themselves against non-Slavic powers such as Fascist Italy.