History of Poland
The Polish People's Republic ("Polska Rzeczpospolita Ludowa") was established under the rule of the communist Polish United Workers' Party (PZPR). The name change from the Polish Republic was not officially adopted, however, until the proclamation of the Constitution of the Polish People's Republic in 1952.
History of Poland (1945–1989)
In December 1989, changes to the Polish constitution were made, officially eliminating the "socialist" order: Marxist references were removed and the name of the country was changed back to the Polish Republic.