 The question of shifting populations and religious conversion of the Croats was to be left aside until the Serbs had assumed power in Yugoslavia.Revenge was incorporated into the Chetnik manual as a "... sacred duty of the Serbian people against those who had wronged them during the war and occupation".Chetnik uprisings, often in conjunction with the Partisans, against Axis occupation forces began in early July 1941 in Western Serbia.