Following the Treaty of Versailles, Chełmno Land was returned to Poland in January 1920, after the Poles regained independence in 1918. In the interwar period it formed the southern part of the Pomeranian Voivodeship with the capital in Toruń. It was occupied after the Invasion of Poland in September 1939 by Nazi Germany and unilaterally annexed in October, however, lacking any international recognition. During the occupation, the Germans carried out the "Intelligenzaktion", a planned mass murder of the local Polish elites. Already in autumn of 1939, about 23,000 Poles of the pre-war Pomeranian Voivodeship were murdered. In January 1945 it was captured by the Red Army and the German occupation of this part of Poland ended.