History of Poland (1945–89)

The history of Poland from 1945 to 1989 spans the period of Soviet communist dominance imposed after the end of World War II over what had become the Polish People's Republic. These years, while featuring general industrialization and urbanization and many improvements in the standard of living in Poland, were marred by social unrest and severe economic difficulties.

Near the end of World War II, the advancing Soviet Red Army pushed out the Nazi German forces from occupied Poland. In February 1945, the Yalta Conference sanctioned the formation of a provisional government of Poland from a compromise coalition, until postwar elections. Joseph Stalin, the leader of the Soviet Union, manipulated the implementation of that ruling. A practically communist-controlled Provisional Government of National Unity was formed in Warsaw by ignoring the Polish government-in-exile based in London since 1940.

During the subsequent Potsdam Conference in July–August 1945, the three major allied powers ratified the colossal westerly shift of Polish borders and approved its new territory between the Oder–Neisse line and Curzon Line. Following the destruction of the Polish-Jewish population in the Holocaust, the flight and expulsion of Germans in the west, resettlement of Ukrainians in the east, and the repatriation of Poles from Kresy, Poland became for the first time in its history an ethnically homogeneous nation-state without prominent minorities. The new government solidified its political power over the next two years, while the communist Polish United Workers' Party (PZPR) under Bolesław Bierut gained firm control over the country, which would become part of the postwar Soviet sphere of influence in Central and Eastern Europe.