 The Kingdom of Serbs, Croats and Slovenes changed its name in 1929 to the Kingdom of Yugoslavia and the present-day Republic of North Macedonia was included as South Serbia in a province named Vardar Banovina.During World War II, Axis forces occupied much of the Kingdom of Yugoslavia from 1941.Bulgaria as an associate of the Axis powers advanced into the territory of the Republic of North Macedonia and the Greek province of Macedonia in 1941.