Battles & Wars › Between the wars
Spanish Civil War
July 1936 – April 1939· War· Europe
Well documentedSolid records, physical evidence or scientific consensus.
Spain's civil war between the elected Republic and Nationalist rebels under General Francisco Franco, which Franco won in 1939.
See it on the Battles & Wars map →What happened
In July 1936 army officers rose against the left-leaning Republic. The coup failed in Madrid and Barcelona, splitting Spain. Nazi Germany and Fascist Italy sent the Nationalists planes, tanks and troops; the Soviet Union armed the Republic, and about 35,000 foreign volunteers fought for it in the International Brigades. Britain and France stayed out. Both sides carried out mass killings behind the lines. Franco took Madrid in March 1939. Estimates of deaths, including executions, range from about 300,000 to 500,000.
Why it matters
It was a rehearsal for World War II, testing German and Italian weapons and tactics, and brought Franco's dictatorship, which lasted until his death in 1975.
How we know
Government and military archives, mass-grave excavations still under way, accounts by journalists and volunteers such as George Orwell's Homage to Catalonia, and Picasso's Guernica.
Still debated
Death tolls, especially of executions behind the lines, are still being counted, and Spain still argues over how to remember the war.
Inside this (1)
Connections (3)
▸Bombing of Guernica shocked the world during Spanish Civil WarWell documented
The connection
The raid came during Franco's campaign to take the Basque country in the north. Reported worldwide within days, it turned much foreign opinion against the Nationalists and their German allies, and Picasso painted Guernica for the Republic's pavilion at the 1937 Paris World's Fair. Militarily it changed little; Bilbao fell in June.
When and how
Guernica, Basque Country, April 26, 1937, during the Nationalist offensive in Biscay; George Steer's report ran in The Times and The New York Times on April 28.
How we know
Newspaper archives, diplomatic reports and Picasso's painting, finished in June 1937, show the immediate global reaction.
Debates and open questions
Franco's Spain long claimed Republicans burned the town themselves; Germany formally apologized only in 1997. How far the outcry affected foreign policy is debated.
▸Spanish Civil War was a testing ground for World War IIMostly agreed
The connection
Germany and Italy sent troops, planes and tanks to Franco, while the Soviet Union aided the Republic. Germany's Condor Legion tested new aircraft, dive-bombing and the bombing of towns, as at Guernica in 1937, and trained pilots later used in 1939–41. Britain and France stayed out, signaling to Hitler that the democracies would avoid confrontation.
When and how
Spain, 1936–39: Germany's Condor Legion and Italian troops for Franco; Soviet advisers and volunteer International Brigades for the Republic.
How sure are we?
Luftwaffe records and Condor Legion veterans' later careers show the transfer of methods; at Nuremberg, Göring said he had used Spain to test his young air force.
Debates and open questions
Some lessons were misread: Spain seemed to show bombers could defend themselves, and some armies drew the wrong conclusions about using tanks.
▸Messerschmitt (Bf 109, Me 262) combat-tested the Bf 109 in the Spanish Civil WarWell documented
The connection
Germany sent the Condor Legion to support Franco's Nationalists. Bf 109s arrived in 1937 and outclassed the Soviet-supplied fighters of the Republic. Pilots such as Werner Mölders developed the loose 'finger-four' formation there, later adopted by most air forces. Spain gave Germany combat-tested aircraft and tactics before World War II began.
When and how
Spain, spring 1937 – 1939; the Condor Legion's fighter group, Jagdgruppe 88.
How we know
Luftwaffe and Condor Legion records and pilots' accounts document the deployments and the tactics developed.
Debates and open questions
Some lessons from Spain misled Germany, for example encouraging faith in dive-bombing and too little interest in long-range escort fighters.