The Socialist Republic of Serbia (), previously known as the People's Republic of Serbia (), was one of the six constituent republics of the Socialist Federal Republic of Yugoslavia in what is now the modern day states of Serbia and the disputed territory of Kosovo. Its formation was initiated in 1941, and achieved in 1944–1946, when it was established as a federated republic within Yugoslavia. In that form, it lasted until the constitutional reforms from 1990 to 1992, when it was reconstituted, as the Republic of Serbia within the Federal Republic of Yugoslavia. It was the largest constituent republic of Yugoslavia, in terms of population and territory. Its capital, Belgrade, was also the federal capital of Yugoslavia. History World War II After the collapse of the Kingdom of Yugoslavia in the April War (1941), the entire country was occupied and partitioned between Axis powers. Central territories of Serbia and the northern region of Banat were occupied by Nazi Germany, that enforced direct control over the Territory of the Military Commander in Serbia, with a puppet Government installed in Belgrade. Southern regions of Metohija and Kosovo were occupied by Fascist Italy and annexed into the Italian Albania. Region of Bačka was annexed by Hungary, while Syrmia was possessed by the Independent State of Croatia. Southeastern parts of Serbia were occupied by Bulgaria. At the beginning of the occupation, there were two resistance movements: Chetniks and Partisans. They had conflicting ideological and political programs, and by 1943, Chetniks started to collaborate with Axis forces. Partisans advocated transformation of Yugoslavia into a federation, with Serbia becoming one of its federal units. In the autumn of 1941, first provisional institutions were established by partisans in some liberated territories, headed by the Main National Liberation Committee for Serbia. It was seated in Užice, and thus the movement became known as the Republic of Užice. However, the German offensive crushed this proto-state in December of the same year. After that, main partisan forces moved to Bosnia. People's Republic of Serbia Serbia was liberated in the autumn of 1944, by partisan forces and the Red Army. Soon after the liberation of Belgrade on 20 October, creation of new administration was initiated. In November 1944, the Anti-fascist Assembly for the People's Liberation of Serbia was convened, affirming the policy of reconstituting Yugoslavia as a federation, with Serbia as one of its federal units. Thus was laid the foundation