In early May 1937, a separate battalion began to organize for the Canadians in Spain. When it was formally organized at Albacete, Spain in July 1937, the volunteers named it for William Lyon Mackenzie and Louis-Joseph Papineau. These men had led the Rebellion of 1837–1838 in Canada. They became noted politicians in the 19th century, standing for a clean and responsible government. The Canadian volunteers chose this name as a symbol of their national identity and commitment to the Republican government’s side.