 On 22 June 1941, the 1st Sisak Partisan Detachment was formed near Sisak, as the first military unit formed by a resistance movement in occupied Europe.This sparked the beginning of the Yugoslav Partisan movement, a communist multi-ethnic anti-fascist resistance group led by Josip Broz Tito.The movement grew rapidly and at the Tehran Conference in December 1943 the Partisans gained recognition from the Allies.