The Battle of the Ebro was the longest and largest battle of the Spanish Civil War and the greatest, in terms of manpower, logistics and material ever fought on Spanish soil. It took place between July and November 1938, with fighting mainly concentrated in two areas on the lower course of the Ebro River, the Terra Alta comarca of Catalonia, and the Auts area close to Fayón (Faió) in the lower Matarranya, Eastern Lower Aragon. These sparsely populated areas saw the largest array of armies in the war. The battle was disastrous for the Second Spanish Republic, with tens of thousands left dead or wounded and little effect on the advance of the Nationalists.

Juan Negrín López was a Spanish physician and politician who served as prime minister of the Second Spanish Republic. He was a leader of the Spanish Socialist Workers' Party and of the left-leaning Popular Front government during the Spanish Civil War. He also served as finance minister. He was the last Loyalist premier of Spain (1937–1939), leading the Republican forces defeated by the Nationalists under General Francisco Franco. He was President of the Council of Ministers of the Second Spanish Republic and the Spanish Republican government in exile between 1937 and 1945. He died in exile in Paris, France.