During the later stages of World War II and the post-war period, Reichsdeutsche (German citizens) and Volksdeutsche (ethnic Germans living outside the Nazi state) fled and were expelled from various Eastern and Central European countries, including Czechoslovakia, and from the former German provinces of Lower and Upper Silesia, East Prussia, and the eastern parts of Brandenburg (Neumark) and Pomerania (Farther Pomerania), which were annexed by the Provisional Government of National Unity of Poland and by the Soviet Union.
The idea to expel the Germans from the annexed territories had been proposed by Winston Churchill, in conjunction with the Polish and Czechoslovak governments-in-exile in London since at least 1942. Tomasz Arciszewski, the Polish prime minister in-exile, supported the annexation of German territory but opposed the idea of expulsion, wanting instead to naturalize the Germans as Polish citizens and to assimilate them. Joseph Stalin, in concert with other Communist leaders, planned to expel all ethnic Germans from east of the Oder and from lands which from May 1945 fell inside the Soviet occupation zones. In 1941, his government had already transported Germans from Crimea to Central Asia.