The Brigade, under Colonel Adam Zakrzewski, was part of the Pomorze Army. On September 1, 1939, parts of the 18th Regiment of Pomeranian Uhlans made the legendary charge at Krojanty, during which unit's commandant, Colonel Kazimierz Mastalerz was killed. On September 2, the Brigade was ordered to attack the town of Koronowo, which was defended by the German 3rd Armored Division of General Leo Geyr von Schweppenburg. This move was necessary, as it would help the withdrawing 9th Infantry Division, which had been engaged in bitter fighting. The cavalrymen, with heavy losses, managed to halt the Germans. However, at Bukowiec the Wehrmacht forces destroyed the 16th Regiment of Greater Poland Uhlans, soon afterwards the 18th Regiment of Pomeranian Uhlans shared same fate. The remaining forces managed to withdraw from the Tuchola Forest and on September 5, became part of the Operational Group of General Juliusz Drapella. After a few days, these units, together with Podolska Cavalry Brigade, took part in the Battle of Bzura. Then they managed to break to the Kampinos Forest, where, together with Podolska Cavalry Brigade and Wielkopolska Cavalry Brigade they created the Joint Cavalry Brigade of General Roman Abraham. On September 20, these forces broke into besieged Warsaw, where they capitulated together with the city, on September 28, 1939.