The 1st Light Tank Battalion (49 single turret tanks) fought in the ranks of the Prusy Army as part of the strategic reserve force of the Polish Army. It entered combat on September 4, 1939, and fought with distinction in a variety of roles, mostly as a mobile reserve and for covering the withdrawal. It fought in a number of battles, most notably in the battles of Przedbórz, Sulejów, Inowłódz, Odrzywół and Drzewica. On September 8 it managed to stop the German advance on the centre of the Polish forces, but the following day it got separated from the main force and had to be withdrawn to the rear. Part of the battalion was destroyed in the Battle of Głowaczów, while the remainder on September 13 managed to break through to the other side of the Vistula, where it joined the Lublin Army and Col. Stefan Rowecki's Warsaw Armoured Motorised Brigade. As part of that unit, the battalion took part in the Battle of Józefów and formed part of the spearhead of the Polish units trying to break through to Lwów and the Romanian Bridgehead. After the Battle of Tomaszów Lubelski, on September 21, 1939, the remaining tanks were destroyed by their crews and the unit surrendered to the Germans.