Nomadic tribes sporadically invaded and conquered the disparate peoples living in South Slav lands from Roman times until the nineteenth century. The Serbs resisted but fell under foreign domination for nearly 500 years after the Ottoman Empire defeated them at the Battle of Kosovo Polje in 1389. Of the peoples forming modern Yugoslavia, only the Montenegrins remained independent through the centuries of foreign domination.
The South Slavs were intensely involved in the military maneuvers, power politics, and alliances in Europe that precipitated World War I. In 1912 Serbia joined its smaller neighbors to drive the Ottoman Empire from Macedonia in the First Balkan War. The following year, Serbia successfully contested Bulgarian claims to that territory in the Second Balkan War. During the world war that followed, Serbia was attacked by Austria-Hungary and Germany on northern and southern fronts, and it paid dearly for its earlier victories. In October 1915, Serbian forces retreated from Belgrade to the Adriatic Sea. Evacuated to Greece to fight under a French command, they eventually participated in the defeat of the Central Powers and liberation of Serbia.
Like other small states during the years between the world wars, the Kingdom of the Serbs, Croats, and Slovenes sought protection in alliances and collective security arrangements. It allied with Czechoslovakia and Romania and signed a treaty of friendship with France. It joined the Little Entente with Romania, Greece, and Turkey in 1933. This pact obligated each signatory to defend existing borders in southeastern Europe against aggression by revisionist powers. Nevertheless, for selfprotection , Yugoslavia gravitated toward Germany and Italy when the major European powers failed to oppose Axis expansionism in the late 1930s. Yugoslavia declined a belated French offer to conclude a mutual assistance pact in 1937. The policy of accommodation to the Axis powers culminated in Yugoslav accession to the pro-Nazi Tripartite Pact on March 25, 1941.
Outraged at the government's cooperation with Nazi Germany, air force general Dusan Simovic led a group of military officers in a swift coup d'état. They declared their objections to, but were careful not to abrogate, the Tripartite Pact. Despite their caution, Germany leveled Belgrade with a massive air strike and began a full-scale ground invasion of Yugoslavia in April 1941, without a formal declaration of war.
Data as of December 1990