After the German invasion in September 1939, the Polish state was seized by two aggressors, the Third German Reich and the Soviet Union. Despite the defeat, the Poles did not stop fighting. In France, they established civil and military authorities with President Władysław Raczkiewicz (1885-1947) and General Władysław Sikorski (1881-1943), acting as prime minister and commander-in-chief along with the Polish military in France and later in Great Britain. On September 27, 1939, in Warsaw, the underground organization Service for Poland’s Victory (SZP) was set up. Its commander was General Michał Tokarzewski-Karaszewicz (1893-1964). In November 1939, the Service for Poland’s Victory was dissolved, and in its place, General Sikorski established the Union for Armed Struggle (ZWZ), with General Kazimierz Sosnowski (1885-1969) acting as its first commander. At the end of June 1940, General Stefan Rowecki (1895-1944) was appointed the new general commander of the ZWZ. Conspiratorial structures were created in the territories occupied by both Germany and the Soviet Union. On February 14, 1942, General Władysław Sikorski issued an order to transform the Union for Armed Struggle into the Home Army. General Stefan Rowecki remained the head of the organization until his arrest by the Germans in Warsaw on June 30, 1943. The next AK commanders were General Tadeusz Komorowski (1895-1966), and then General Leopold Okulicki (1898-1946), who on January 19, 1945, gave the order dissolving the structures of the Home Army.

As part of its activities, the Home Army waged the so-called current struggle (including sabotage, intelligence and propaganda actions), but also prepared a general uprising. The most spectacular actions carried out by the Home Army include obtaining detailed information on the production of V-1 and V-2 missiles in Peenemünde on the island of Usedom, including the acquisition of a V-2 rocket and delivering essential parts to Great Britain. At its peak, that is in the summer of 1944, about 380,000 soldiers served in the Home Army.