In August 1939, with prospect of war growing, the division was ordered to defend southwestern sector of the Polish Corridor between Bydgoszcz and Naklo as part of the Pomorze Army.[1] The division was composed of :
59e Infantry Regiment
61st Infantry regiment
62nd Infantry Regiment
15th Light Artillerie Regiment
Backed by some field fortifications and located along the Brda river, it successfully defended attacks of the 50th Infantry Division and the Netze Brigade of the Wehrmacht between September 1 and 2. Its rear units, remaining in Bydgoszcz, took part in the Bloody Sunday (1939), on September 3. On the same day, the division was ordered to retreat towards Toruń, continually attacked by the Wehrmacht and the Luftwaffe. Between September 9 and 18, the unit took part in the Battle of the Bzura, covering rear areas of Polish troops. After Polish defeat, the division gathered around Palmiry, with 1500 soldiers still alive. Without heavy equipment, and after several skirmishes with the Germans, the remains managed to reach Warsaw on September 23 (see: Siege of Warsaw (1939)).