sentences:  The "Mac-Paps" fought bravely in many battles but were forced to leave Spain in 1938 by Prime Minister Juan Negrín López along with the other foreign volunteers as it became clear that the war was lost.Of the nearly 1,500 Canadians known to have fought in Spain, 721 were verified as having lost their lives.The most famous Canadian to serve in the Mackenzie–Papineau Battalion was Dr. Norman Bethune, a surgeon who would invent the world's first mobile medical unit.