Following the collapse of Austria-Hungary in October 1918, the regions of Banat, Bačka and Baranya came under control of the Serbian army, in November.

On November 25, 1918, the Great National Assembly of Serbs, Bunjevci and other Slavs (Велика народна скупштина Срба, Буњеваца и осталих Словена, Velika narodna skupština Srba, Bunjevaca i ostalih Slovena) German: Große Volksversammlung der Serben, Bunjewatzen und der übrigen Slawen) from Banat, Bačka and Baranya, voted that these regions join to the Kingdom of Serbia.

Although the government in Belgrade accepted the decision that Banat, Bačka and Baranya had joined Serbia, it did not recognize the People's Administration.

The population of Banat, Bačka and Baranya (within the borders defined by the peace conference) was 1,365,596, including 29.1% Serbs, 27.71% Hungarians, 23.10% Germans, and others[1][failed verification – see discussion][2] (such as Romanians).

The Great People's Council consisted of 50 members, which included 35 Serbs, 8 Bunjevci, 5 Slovaks, 1 Krashovan, and 1 Uniate priest.