The origins of the YPA can be found in the Yugoslav Partisans of World War II. As part of the anti-fascist People's Liberation War of Yugoslavia, the People's Liberation Army of Yugoslavia (NOVJ), a predecessor of the YPA, was formed in the Bosnian town of Rudo on 22 December 1941. After the Yugoslav Partisans liberated the country from the Axis Powers, that date was officially celebrated as the "Day of the Army" in the Socialist Federal Republic of Yugoslavia (SFR Yugoslavia).