During the siege of Warsaw, on the night of 26/27 September 1939, at the initiative of Brig. Gen. Michał Karaszewicz-Tokarzewski and an order of the Supreme Commander, Marshall Edward Rydz-Śmigły, the first underground organization was established - the Służba Zwycięstwu Polski /Polish Victory Service -PVS/.
The PVS was a nation-wide organisation of a military-political nature, whose aim was to fight for the independence of Poland within the borders existing before 1 September 1939.
In 1939, by virtue of a decision of the highest authorities of the Republic of Poland in exile, the Polish Victory Service was transformed into the Association of Armed Struggle /AAS/. Initially, Lt. Gen. Kazimierz Sosnkowski became the Head Commander of the AAS (military organisation), who formally commanded from Paris. Maj. Gen. Stefan Rowecki "Grot" served as functional commander of the AAC commander within the German occupied area, who was appointed the Head Commander of the AAC on 30 June, after the Head Command was moved to Poland.
The author of the AAS, Gen. Karaszewicz -Tokarzewski, was appointed as AAS commander in the Soviet occupied area. In March 1940 he was arrested while crossing the border.
Other military organizations were set up in conjunction with the AAS. This became the reason for conducting a uniting campaign. On 14 February 1942 in place of the AAS the Home Army was created, to which most of the underground organizations of an armed nature were gradually subordinated to.
In 1943 the expanding Home Army numbered 380.000 soldiers throughout Poland. It was the most powerful underground army in occupied Europe.
Activity of the Home Army covered diversion and sabotage, intelligence and counter-intelligence, military training and arms production, communications, the Bureau of Information and Propaganda (BIP), and the Legalization Department (production of false documents). Preparations towards a nationwide universal uprising were carried out. For the entire duration of the occupation the "Biuletyn Informacyjny" /a weekly covertly published in occupied Poland/ was released as the successive PVS-AAS-Home Army organ, being the most important magazine of the underground Poland and Europe (circulation reached 20.000 copies).
On 30 June 1943 the Commander of the Home Army - Gen. Stefan Rowecki "Grot" was arrested, which was a huge blow to the Polish underground. In this situation, Gen. Tadeusz Komorowski "Bor", "Grot's" second-in-command, assumed command, serving at this post until the collapse of the Warsaw Rising.
The last Home Army commander (appointed 1 October 1944 by Gen. "Bor") was Gen. Leopold Okulicki "Niedźwiadek". On 19 January 1945, in the face of an offensive by the Red Army, the Home Army was dissolved. In its place, "Nie" was set up, assuming the task of fighting for independence under Soviet occupation.