Polish resistance movement in World War II

The Polish resistance movement in World War II, with the Polish Home Army at its forefront, was the largest underground resistances in all of Nazi-occupied Europe, covering both German and Soviet zones of occupation. The Polish defence against the Nazi occupation was an important part of the European anti-fascist resistance movement. It is most notable for disrupting German supply lines to the Eastern Front, providing military intelligence to the British, and for saving more Jewish lives in the Holocaust than any other Allied organization or government. It was a part of the Polish Underground State.

The largest of all Polish resistance organizations was the Armia Krajowa (Home Army, AK), loyal to the Polish government in exile in London. The AK was formed in 1942 from the Union for Armed Combat (Związek Walki Zbrojnej or ZWZ, itself created in 1939) and would eventually incorporate most other Polish armed resistance groups (except for the communists and some far-right groups). It was the military arm of the Polish Underground State and loyal to the Polish government in Exile.

Most of the other Polish underground armed organizations were created by a political party or faction, and included:

The largest groups that refused to join the AK were the National Armed Forces and the pro-Soviet and communist People's Army (Polish Armia Ludowa or AL), backed by the Soviet Union and established by the Polish Workers' Party (Polish Polska Partia Robotnicza or PPR).

...
Wikipedia