 However, in terms of international politics, a far more important victory was won by Joseph Stalin already in 1943, when the Western Allies yielded to his demands during the Tehran Conference, for the annexation of eastern Poland by the Soviet Union.With full Soviet control and sponsorship, in July 1944, the Polish Committee of National Liberation ("Polski Komitet Wyzwolenia Narodowego", PKWN), a Polish provisional government was formed.Its purpose was to administer the territories earmarked for the return to the newly reformed Poland.