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.
Polish Underground State
In many respects, the history of the Polish Underground State mirrors that of the Polish non-communist resistance in general. The Underground State traces its origins to the Service for Poland's Victory (Służba Zwycięstwu Polski, SZP) organization, which was founded on 27 September 1939, one day before the surrender of the Polish capital of Warsaw, at a time when the Polish defeat in the German invasion of Poland (accompanied by the Soviet one) appeared inevitable. SZP founder General Michał Karaszewicz-Tokarzewski received orders from Polish Commander-in-Chief Marshal Edward Rydz-Śmigły to organize and carry out the struggle in occupied Poland. Karaszewicz-Tokarzewski decided that the organization he was creating needed to move beyond a strictly military format; and in line with the traditions of the underground 19th-century Polish National Government and World War I-era Polish Military Organization, it would need to encompass various aspects of civilian life. Hence, the SZP, in contact with (and subordinate to) the Polish Government in Exile, envisioned itself not only as an armed resistance organization, but also as a vehicle through which the Polish state continued to administer its occupied territories.