By the time of the Yalta Conference , in February 1945 , the Soviets were at the height of their power , while the fronts in Western Europe and Italy had not advanced as quickly as expected . At the conference , the Allies continued their discussions and informally finalized decisions on the postwar order in Europe . Churchill and Roosevelt accepted the Curzon Line as the basis of Poland 's eastern border , but disagreed with Stalin on the extent of Poland 's western expansion , at the expense of Germany . Poland was going to get a compromise provisional ( until the agreed free elections ) government of national unity including both the existing communist government , now unofficially considered principal , and pro-Western forces . There was a disagreement regarding the issue of inclusion of the London-based government in exile as the main pro-Western faction in the government of national unity . The Polish government in exile reacted to the Yalta announcements ( unlike the Tehran Conference outcomes , Yalta results were made public ) with a series of fervent protests . The Underground State in Poland , through its Council of National Unity that operated in hiding , issued a more measured and pragmatic response , regretting the sacrifices imposed on Poland but expecting a representative government established and committing itself to adapt to the situation and to promote " friendly and peaceful relations " with the Soviet Union . The council declared its readiness to participate in the consultations leading to the formation of the government of national unity
Yalta Conference
Yalta Conference
History of Poland (1939–1945)