First Legions Infantry Regiment was the oldest of all regiments of the Polish Army in the interbellum period. Its traditions dated to the First Cadre Company, which on August 6, 1914 marched from Austrian Galicia into Russian-controlled Congress Poland. Furthermore, it was based on the First Legions Regiment, part of Polish Legions in World War I, which existed from 1914 until 1917, and fought with distinction in the Battle of Łowczówek, Battle of Tarłów and Battle of Kostiuchnówka.