The outbreak of the Spanish Civil War was triggered by a military coup led by General Franco against the government of the Spanish Republic on July 18, 1936. The subsequent suppression of the popular uprising by the Spanish population in many parts of the country triggered a wave of solidarity, especially among German emigrants. Through the intervention of Hitler and Mussolini on the side of Franco, Spain was to become the preeminent symbol for the fight against fascism and for the defence of freedom and democracy.

In February 1936 members of the Parisian Lutetia Circle, which included writers with communist, social democratic and bourgeois sympathies such as Heinrich and Klaus Mann, Ernst Toller, Lion Feuchtwanger, Arnold Zweig and Oskar Maria Graf called for the creation of a German popular front against Nazism resulting in a large solidarity movement which conducted appeals, rallies and gatherings. Thomas Mann wrote an editorial for a special edition issued by the Association of German Writers in Exile and titled Spanien (Spain).

With the Soviet Union's support of the Republican troops, the civil war soon became a proxy war. Thousands of volunteers from more than ten European countries joined the ranks of the Spanish Republic's International Brigades including intellectuals and writers like André Malraux, Ernest Hemingway and George Orwell. The German artists and writers who participated as combatants or reporters in the Civil War were mainly those with communist sympathies such as Ludwig Renn, Gustav Regler, Alfred Kantorowicz, Ernst Busch and Arthur Koestler.

The hope that Franco (and therefore Hitler) would be defeated in Spain thus putting a stop to the spread of fascism in Europe remained until a few months before the war ended on 1 April 1939. Thousands of Spanish refugees, civilians as well as soldiers, who had fled to France in the face of looming defeat were interred by the French Government in assembly camps such as St. Cyprien, Gurs and Le Vernet. Soon, these assembly centres evolved into prison camps, predominantly holding combatants from the Spanish Civil War from all over Europe. In July 1941 many of them were transferred to German concentration camps.

Further reading:
Berg, Angela: Die internationalen Brigaden im Spanischen Bürgerkrieg 1936-1939. Essen: Klartext-Verlag 2005
Kantorowicz, Alfred: Spanisches Kriegstagebuch. Hamburg: Konkret Literatur Verlag 1979
Mühlen, Patrik von zur: Spanien war ihre Hoffnung. Die deutsche Linke im Spanischen Bürgerkrieg 1936 bis 1939. Berlin: Dietz Verlag 1985