The Third Brigade was formed on 8 May 1915, as part of the Polish Legions in World War I. The Brigade commanders included: Zygmunt Zieliński (April 1915 - September 1915), Wiktor Grzesicki (September 1915 - July 1916), Stanisław Szeptycki (July 1916 - October 1916), and Bolesław Roja (?). In 1917 the III Brigade together with the I Brigade followed Józef Piłsudski during the Oath crisis, refusing to swear the oath, and was disbanded.