In late 1921 a border adjustment between the Weimar Republic and Poland took place as a result of the Silesian Uprisings. The uprising were a series of three armed rebellions that took place between 1919 and 1921 by the Polish people in the Upper Silesia region against the Weimar Republic. The Polish people of the region wanted to join the Second Polish Republic, which had been established following World War I. The 1919 Treaty of Versailles had called for a plebiscite in Upper Silesia in 1921 to determine whether the territory should be a part of Germany or Poland.