World War II in Yugoslav Macedonia started with the Axis invasion of Yugoslavia in April 1941. Under the pressure of the Yugoslav Partisan movement, part of the Macedonian communists began in October 1941 a political and military campaign to resist the occupation of Vardar Macedonia. Officially, the area was called then Vardar Banovina, because the very name Macedonia was prohibited in the Kingdom of Yugoslavia. It was occupied mostly by Bulgarian, but also by German, Italian, and Albanian forces.
Initially there was no organised resistance because the majority of the Macedonian Slavs were pro-Bulgarian oriented. It started to grow only in 1943 with the capitulation of Italy and the Soviet victories over Nazi Germany. The role of the Bulgarian communists, who avoided organizing mass armed resistance, was also a key factor. Their influence over the Macedonian Party organization remained dominant until 1943, when it became obvious that Germany and Bulgaria would be defeated.
At that time Tito's special emissary Svetozar Vukmanović arrived in Macedonia. Vukmanović had to activate the struggle and give it an ethnic Macedonian identity. This led to the rise of younger generation anti-Bulgarian oriented partisan leaders, who were loyal to Yugoslavia. They formed in 1943 the People's Liberation Army of Macedonia and the Macedonian Communist Party. In the western part of the area, the Albanian Partisans also participated in the resistance movement.
After Bulgaria switched sides in the war in September 1944, the Bulgarian 5th. Army stationed in Macedonia, moved back to the old borders of Bulgaria. In the early October the newly formed Bulgarian People's Army together with the Red Army reentered occupied Yugoslavia to blocking the German forces withdrawing from Greece. Yugoslav Macedonia was liberated in end of November when communist Yugoslavia was established. After the German retreat forced by the Bulgarian offensive, the conscription of Macedonians in the army increased significantly.
The operation was commonly called by the Yugoslav Marxist historiography the National Liberation War of Macedonia () in Yugoslavia, similarly to the greater Yugoslav People's Liberation War. Some of the combatants also developed aspirations for independence of the region of Macedonia, but were suppressed at the end of the war by the communist authorities. It marked the defeat of Bulgarian nationalism and the victory of the pro-Yugoslav Macedonism in the area. As result the new Communist authorities persecuted the former collaborationists with the charges of "Great Bulgarian chauvinism" and cracked down on pro-Bulgarian organisations that supported ideas of Greater Bulgaria and those which opposed the Yugoslav idea and insisted on Macedonian independence.
Background
The Balkan Wars in 1912 and 1913, and the World War I (1914-1918) divided the region of Macedonia amongst the Kingdom of Greece, the Kingdom of Bulgaria and the Kingdom of Serbia. The territory was up until that time part of the Ottoman Empire. In those days, the majority of the Slavic speakers in Ottoman Macedonia considered themselves to be a part of the Bulgarian people.
From 1912 until 1915 the territory of Vardar Macedonia remained within the territory of Serbia. In the parts administered by Serbia the new authorities forced out most of the Bulgarian priests and teachers, and began implementing a forceful state-sponsored Serbianisation of Slavic-speaking Macedonians. It was occupied by Kingdom of Bulgaria during World War I between 1915 and 1918. Afterwards it was restored back to Serbia and consequently included as part of the Vardar Banovina in the Kingdom of Yugoslavia. During that period, there were two main autonomist agendas. The right-wing Internal Macedonian Revolutionary Organization (IMRO) led by Ivan Mihailov, was in favor of the creation of a pro-Bulgarian Macedonian state under German and Italian protection.
The leftist IMRO (United) group, who merged with the communists prior to the beginning of the war, favored creation of an independent "Soviet Macedonia" within a Balkan Federation. This option was supported by Pavel Shatev, Dimitar Vlahov, Metodi Shatorov, Panko Brashnarov, and others. However such Macedonian activists, who came from the Bulgarian Communist Party, never managed to get rid of their pro-Bulgarian bias.
During the interwar period in Vardar Macedonia, some young locals repressed by the Serbs, tried to find a separate Macedonian way of national development. Nevertheless, the existence of considerable Macedonian national consciousness prior to the middle of the 1940s is disputed. At that time anti-Serbian and pro-Bulgarian feelings among the local population prevailed.