Population exchange between Poland and Soviet Belarus

The population exchange between Poland and Soviet Belarus at the end of World War II (1944–1947) was based on an agreement signed on 9 September 1944 by the Byelorussian SSR with the newly-formed Polish Committee of National Liberation (PKWN). It stipulated the resettlement of ethnic Belarusians from Poland to Belarus and of ethnic Poles and Jews who had Polish citizenship before September 17, 1939 (date of the Soviet Invasion of Poland) from Belarus to Poland, in accordance with the resolutions of the Yalta and Tehran conferences and the plans about the new Belarus–Poland border.

Source: Wikipedia — Population exchange between Poland and Soviet Belarus (CC BY-SA 4.0)