premise: Yugoslavia existed.
hypothesis: Yugoslavia ( Jugoslavija / Југославија , Jugoslavija , Југославија ) was a country in Southeast Europe during most of the 20th century . It came into existence after World War I in 1918 under the name of the Kingdom of Serbs , Croats and Slovenes by the merger of the provisional State of Slovenes , Croats and Serbs ( itself formed from territories of the former Austro-Hungarian Empire ) with the formerly independent Kingdom of Serbia . Yugoslavia was renamed the Federal People 's Republic of Yugoslavia in 1946 , when a communist government was established . In 1963 , the country was renamed again as the Socialist Federal Republic of Yugoslavia ( SFRY ) . After an economic and political crisis in the 1980s and the rise of nationalism , Yugoslavia broke up along its republics ' borders , at first into five countries , leading to the Yugoslav Wars .