By the time of the Yalta Conference in February 1945 , the communists had already established a Provisional Government of the Republic of Poland . The Soviet position at the conference was strong because of their decisive contribution to the war effort and as a result of their occupation of immense amounts of land in central and eastern Europe . The Great Powers gave assurances that the communist provisional government would be converted into an entity that would include democratic forces from within the country and active abroad , but the London-based government-in-exile was not mentioned . A Provisional Government of National Unity and subsequent democratic elections were the agreed stated goals . The disappointing results of these plans and the failure of the Western powers to ensure a strong participation of non-communists in the immediate post-war Polish government were seen by many Poles as a manifestation of Western betrayal
Yalta Conference
Yalta Conference
History of Poland