Over the next year, the Mackenzie–Papineau Battalion fought in several major battles, including the Battle of Teruel (December 1937 – March 1938) and the Aragon Offensive (March–April), more commonly known to the Republican forces as the "Retreats." The Finnish-American machine gun companies successfully repelled the Nationalist forces, but the collapse of the front on their flanks forced them to join the withdrawal. Their final engagement was the Battle of the Ebro (July–September). This decisive Nationalist victory broke the back of the Republican forces.