 In 1921, its organized units resisted the Polish rebellion in the Third Silesian Uprising; which was aimed at seceding Upper Silesia from Germany.The "Selbstschutz" were reintroduced during the late 1930s in Poland and Czechoslovakia.The "Selbstschutz" activists worked to indoctrinate ethnic Germans locally and commit acts of terrorism against the Czech population in the Sudetenland.