Mackenzie-Papineau Battalion, collective designation for some 1300 Canadian volunteers who served in international brigades recruited to assist the communist-supported republican government against Franco's fascists during the Spanish Civil War (July 1936-March 1939). There was also an actual battalion, named after the leaders of the Rebellions of 1837, mustered into the XVth "English-Speaking" International Brigade on 1 July 1937, in Albacete, Spain. Other Canadians joined the Abraham Lincoln Battalion, the British Battalion and other units, including medical and transportation detachments.
Dr Norman Bethune, undoubtedly the most famous Canadian there, created and led a blood transfusion service. The "Mac-Paps" fought in 5 major campaigns, including the assault on Fuentes de Ebro on 13 October 1937, the defence of Teruel in December-January, the "Retreats" in March-April 1938, and a counterattack across the Ebro River in the last summer of the war. The battalion was led by Edward Cecil-Smith, the military commander and a Toronto labour journalist, and Saul Wellman, a New York union organizer and the unit's political commissar. When the Mac-Paps withdrew from the conflict in September 1938, it is said, only 35 men were left on their feet.
Although celebrated by well-wishers on their arrival home in early 1939, the survivors, half the original number, received no official welcome. In April 1937 the Canadian government had passed the Foreign Enlistment Act, outlawing participation by Canadians in foreign wars, and the Customs Act, which provided for government control over arms exports. The Mac-Paps were an official embarrassment, and so languished in obscurity until the 1970s when a number of books, films and plays documented their history.