The Second World War began with the German invasion of Poland on 1 September 1939 ; and , on 17 September , in accordance with the Molotov-Ribbentrop agreement , the Soviet Union invaded Poland from the east . By October 1939 , the Second Polish Republic was split in half between two totalitarian powers . Germany occupied 48.4 percent of western and central Poland . Racial policy of Nazi Germany regarded Poles as " sub-human " and Polish Jews beneath that category , validating a campaign of unrestricted violence . One aspect of German foreign policy in conquered Poland was to prevent its ethnically diverse population from uniting against Germany . The Nazi plan for Polish Jews was one of concentration , isolation , and eventually total annihilation in the Holocaust also known as the '' Shoah '' . Similar policy measures toward the Polish Catholic majority focused on the murder or suppression of political , religious , and intellectual leaders as well as the Germanization of the annexed lands which included a program to resettle Germans from the Baltics and other regions onto farms , ventures and homes formerly owned by the expelled Poles including Polish Jews
the expelled Poles
Expulsion of Poles by Nazi Germany
Rescue of Jews by Poles during the Holocaust