1918 annexation of Vojvodina

The annexation of Vojvodina to the Kingdom of Serbia was carried out in November 1918, at the end of World War I, in the context of the creation of Yugoslavia. The ethnically mixed region consisting of parts of Bačka, Banat and Baranya, collectively referred to as Vojvodina by the Serbs, had previously been a part of Austria-Hungary. Parts of the territory were promised by the Allies of World War I to Serbia and Romania in return for participation in the war. At the same time, the National Council of Slovenes, Croats and Serbs based in Zagreb declared an independent state of the South Slavs living in Austria-Hungary at the time, with the intention of forming a wider South Slavic state with Serbia. The Serbian National Committee was convened in Subotica to prepare for the inclusion of Vojvodina into the future wider South Slavic state.

The Royal Serbian Army started to replace the Austro-Hungarian forces in the region following the Armistice of Villa Giusti. The boundaries of Serbian military occupation were determined by mid-November through the Armistice of Belgrade. As the Serbian army approached Novi Sad, the Serbian National Committee debated whether to join the unified state through annexation to Serbia or through representation in the Zagreb-based National Council and the State of Slovenes, Croats and Serbs. The body opted for the latter solution, but its decisions were annulled by the newly-established Serbian military administration.

Regent Alexander, supported by the army and Croatian Serb leader and National Council deputy president Svetozar Pribićević, decided to have Vojvodina annexed to Serbia before any unification. The move was meant to undermine the National Council in Zagreb and rescind acceptance of the recently adopted Geneva Declaration. The document was negotiated between the Serbian Prime Minister Nikola Pašić and the National Council to determine the constitutional framework of the South Slavic unified state. The declaration was accepted by Pašić under international pressure, but the document did not satisfy the interests of Regent Alexander.

After repudiation of the Geneva Declaration, the Great People's Assembly of Serbs, Bunjevci and other Slavs in Banat, Bačka and Baranja was convened in Novi Sad as a popular assembly to give the annexation the guise of self-determination and legitimacy. The delegates largely consisted of representatives of various Slavic ethnic groups of Vojvodina – amounting to 38% of the total population at the time. Non-Slavs, deemed enemy nations, received only token representation. The method of annexation of Vojvodina and the treatment of the National Council caused resentment, especially by the Hungarians towards the Allies and the Croats against the Croatian Serbs. The event encouraged the future king to rule the Kingdom of Serbs, Croats and Slovenes (later renamed Yugoslavia) declared on 1 December in an authoritarian fashion.