Yugoslavia 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 Kingdom of Serbs, Croats and Slovenes by the merger of the provisional State of Slovenes, Croats and Serbs with the formerly independent Kingdom of Serbia and Kingdom of Montenegro. The Serbian royal House of Karađorđević became the Yugoslav royal dynasty. Yugoslavia gained international recognition on 13 July 1922 at the Conference of Ambassadors in Paris. The country was named after the South Slavic peoples and constituted their first union, following centuries in which the territories had been part of the Ottoman Empire and Austria-Hungary.
Renamed Kingdom of Yugoslavia on 3 October 1929, it was invaded by the Axis powers on 6 April 1941. In 1943, a Democratic Federal Yugoslavia was proclaimed by the Partisan resistance. In 1944, the king recognised it as the legitimate government, but in November 1945 the monarchy was abolished. Yugoslavia was renamed the Federal People's Republic of Yugoslavia in 1946, when a communist government was established. It acquired the territories of Istria, Rijeka, and Zadar from Italy.