Between 16 November 1698 and 26 January 1699, the town of Karlovci was the site of a congress that ended the hostilities between the Ottoman Empire and the Holy League, a coalition of various European powers including Habsburg Monarchy, Poland, Venice and Russia; the congress produced the Treaty of Karlowitz.
At the Serb National Assembly in Karlovci in May 1848, Serbs declared the unification of the regions of Srem, Banat, Bačka, and Baranja (including parts of the Military Frontier) into the province of Serbian Vojvodina.