The First Army was a field army of the Polish Army that existed during the Polish-Bolshevist War. In March 1920 the Headquarters of the Army decided to disband the Front HQs active until then and reform them into separate armies. The largest of Polish fronts, the so-called Lithuanian-Belarusian Front (otherwise known as the Northern Front) was split up onto three armies: the 1st, 4th and 7th. The new 1st Army was composed mostly of former Corps-sized operational groups of Generals Edward Rydz and Józef Lasocki. Initially the command of the new formation was given to Gen. Józef Haller de Hallenburg, but eventually he took command of a new Northern Front while the 1st Army was given to Gen. Stefan Majewski. Initially it faced the Red Army's 15th Red Banner Army under Avgust Kork.