World War II
Italy invaded Albania in April 1939, overan the country within a week, forcing its king into exile and making it a part of the Italian Empire. In April 1941, Nazi Germany attacked Greece and Yugoslavia, assisted by Bulgarian forces in the latter case.
German forces occupied Serbia, which was tightly controlled, and set up a puppet-state in Croatia under Ante Pavelić, leader of the extreme nationalist Ustaša movement. This pseudo-independent state included much of Bosnia-Herzegovina. Most of Slovenia was annexed by Germany, while Italy assumed control of Montenegro, the Dalmatian coast, and parts of Bosnia. Macedonia was partitioned between Bulgaria and Albania. Kosovo also became part of Italian-occupied Albania, while eastern Vojvodina was absorbed by Hungary.
Serbian resistance: Chetnik
Different resistance groups developed. In Serbia, General Draža Mihailović led the Chetniks or armed forces loyal to the old régime. When their initial actions prompted massive German retaliation against civilians, they scaled down their efforts. Later, many Chetniks collaborated with the Germans to fight Tito’s Partisans.
Yugoslav resistance: Partisans
The Communist Party of Yugoslavia under Josip Broz Tito led an extensive resistance effort. After Germany attacked Russia, this movement grew in strength, drawing support from different national groups in Yugoslavia. In 1942, Tito declared from his headquarters in the Bosnian town of Bihac, that the national rights of all the peoples of Yugoslavia would be recognized. By mid-1943 his forces, known as Partisans, numbered over 20,000. With the collapse of Italy in September 1943, those numbers increased substantially. Their rapid growth was fueled in part by Allied commitment of support to them alone, as the most active anti-German force in the country. Tito announced the formation of a new federal organization of Yugoslavia in Jacje, November 29, 1943.
Duplicating Nazi crimes, the Ustaša regime in Croatia established concentration camps, at Jasenovac, Stara Gradiska and elsewhere, where hundreds of thousands of Jews, Gypsies, communists, anti-fascist Croats, and Serbs were murdered. Chetnik bands also murdered Muslims in eastern Bosnia and Herzegovina. The total number of deaths from anti-Muslim attacks during January and February 1943 is estimated at 10,000.
In Albania, too, there were different resistance groups: one that could be described as nationalist, a second communist, and a third more diffuse. It was the communists, though, under the leadership of Enver Hoxha, who operated most widely. Although different groups formed a united front in 1942, Hoxha persuaded the Allies that they should only support his Partisan forces, and ultimately succeeded, as Tito did in Yugoslavia. This allowed Hoxha to defeat rivals after the collapse of Italy in 1943.
Tito takes control
In Serbia, while Tito's Partisans battled the Germans, they also fought the Chetniks. The Partisans defeated the Chetniks in the core battleground of Serbia, which positioned them to take power in Yugoslavia at the end of the war.