The International Brigades were foreign Communists who came to Spain to fight against the Nazi-backed Fascist forces of Francisco Franco during the Spanish Civil War (1936–39). The Brigades came from fifty countries and were celebrated by many leftist writers.
On February 21, 1937 the League of Nations Non-Intervention Committee ban on foreign national and stateless volunteers went into effect.
In the Syrian Civil War, Antifa, a terrorist group that operates mainly in America and Western Europe, sent one of it's units, the International Antifascist Brigade, to Syria. Antifa, and other extreme left militant groups, described this as the rebirth of the International Brigades. It claims to be in the region to fight ISIS, but mainly fights the Free Syrian Army, a US ally in the region, as well as Turkey, a valuable NATO ally.