In the following days, the Brigade, together with the whole Poznań Army, withdrew eastwards from Greater Poland. On September 8, 1939, the cavalrymen covered the eastern wing of the Army during the outbreak of the Battle of the Bzura. In the night of September 9–10, 1939, the Brigade attacked the enemy, with initial successes of the 17th Regiment of Greater Poland Uhlans and the 15th Regiment of Poznań Uhlans. However, soon afterwards German defense stiffened and the Brigade halted.