Vojvodina used to be Hungarian but was settled by Serbs during the Ottoman period as refugees, Serbs then started pushing for independence despite it was mixed territory. A lot of the information on wikipedia regarding Vojvodina is mostly Serbian propaganda. So it's hard to find accurate history of Vojvodina. Here also Serbs try to claim they lived in Vojvodina since 900 AD or 600 AD based on other Slavic tribes like Bulgarians etc. Serbs mainly settled in the Balkans in 'Rasca' where their ethnogenesis formed, even the name 'Rascian' an old name for Serb comes from there yet they claim the Bosniaks in Bosnia as Serbs too despite it was settled by various Slavs, even if it had been settled by Serboi tribe the Slavs there diverged from the 'Rascians' and other Slavs.
Vojvodina is an autonomous province that comprises northern Serbia. Before it became part of Yugoslavia in 1920, it was ruled by the Hungarian portion of the Austro-Hungarian Empire
The Hungarians (or Magyars) arrived in the Pannonian Plain during the last decade of the 9th century. Hungarian rule was established in parts of the territory of present-day Vojvodina, beginning from the 10th century. Bačka came under Hungarian rule in the 10th century after the Hungarians defeated Salan. Banat came under Hungarian rule in the 11th century after the defeat of Ahtum, while Syrmia came under Hungarian rule in the 12th century after the Kingdom of Hungary conquered it from the Byzantines
During the 1848 Revolution, the Hungarians demanded independence from the Austrian Empire. Serbs of Vojvodina took action to separate from the Kingdom of Hungary (which was at that time part of Habsburg Austria).