Soon after the defeat in the defensive war of September 1939, clandestine military organizations started to spontaneously spring to life. Their aim was to fight the occupying forces. One of them was the Secret Polish Army founded in November 1939 under the command of Major Jan Włodarkiewicz. When Commander-in-Chief General Władysław Sikorski issued an order to unite the organizations of the Polish Underground and the process began in January 1940, the Secret Polish Army followed the order and in 1941 became part of the Union for Armed Struggle (ZWZ) subordinated to the Polish authorities in exile. The Polish Underground State, operating in the Polish territories under the German and Soviet occupations, was a globally unique phenomenon as an organized underground movement. The clandestine civil structures provided continuity of the major state institutions (including representations of political parties) and ensured the functioning of public institutions such as courts, schools and the press. On the military level, the Home Army (AK) – the Underground Polish Army – was founded.