1918 occupation of Međimurje

In the immediate aftermath of World War I, the region of Međimurje was occupied by forces loyal to the National Council of the State of Slovenes, Croats and Serbs, one of the predecessor states to the Kingdom of Yugoslavia, in November and December 1918. Predominantly inhabited by Croats, this territory was a part of the Kingdom of Hungary until it was captured by Yugoslav forces. The region was annexed by Yugoslavia, which was awarded it at the Paris Peace Conference (1919–1920).

The campaign to capture Međimurje began in November 1918, ostensibly in response to Hungarian actions against a revolt by the population of Međimurje. Major Ivan Tomašević led a 300-strong force that was routed by Hungarian forces near Čakovec, the region's largest town. Pleas for military help from the Royal Serbian Army and the French Armée d'Orient were rebuffed due to obligations assumed under the Armistice of Belgrade between the Entente Powers and Hungary that defined the Drava River as the line of Hungarian control in the area. The National Council mounted a new effort on 24 December, sending a 3,000-strong force made up by Slovene volunteers and much of the Royal Croatian Home Guard. Major Dragutin Perko planned the second incursion into Međimurje in greater detail, and he later commanded a large part of the attacking forces.

Međimurje was captured on 24 December without resistance from the Hungarian garrison. Perko was appointed its administrator, and the region was declared a part of the Kingdom of Serbs, Croats and Slovenes with a reference to the principle of self-determination. The Paris Peace Conference later confirmed the region's accession.