With the invasion of Poland, Nazi Germany conquered the mostly Polish parts of Upper Silesia. Additional lands seized in 1939 were Sosnowiec ("Sosnowitz"), Będzin ("Bendzin", "Bendsburg"), Chrzanów ("Krenau"), and Zawiercie ("Warthenau") counties and parts of Olkusz ("Ilkenau") and Żywiec ("Saybusch") counties. In late 1940 some 18–20,000 Poles were expelled from Żywiec during Action Saybusch. In total, between 1940 and 1944, around 50,000 Poles were forcibly removed from the area and replaced with German settlers from Eastern Galicia and Volhynia. The transfer was agreed upon at the Gestapo–NKVD Conferences. Also, 23 camps called Polenlager were established across Silesia for the expelled Poles. The German populations in Silesia frequently welcomed the Wehrmacht and many thousands of Silesians were subsequently conscripted to the Wehrmacht.