. The
existed for two years, from 1936 until 1938. It is estimated that during the entire
, including 15,000 who died in combat. They participated in the battles of Madrid, Jarama, Guadalajara, Brunete, Belchite, Teruel, Aragon and the Ebro.
was strongly supported by the Comintern and represented the Soviet Union's commitment to assisting the Spanish
Republic (with arms, logistics, military advisers and the NKVD), just as
Fascist Italy,
Fascist Portugal and
Nazi Germany were assisting the opposing Nationalist insurgency. The largest number of volunteers came from
France where the French
Communist Party had many members, and
communist exiles from
Italy and
Germany. Many Jews were part of the brigades, being particularly numerous among the volunteers coming from the
United States, Poland,
France, England, and Argentina.
Republican volunteers who were opposed to Stalinism did not join the Brigades but instead enlisted in the separate Popular Front, the POUM (formed from Trotskyist, Bukharinist and other anti-Stalinist groups, which did not separate Spaniards and foreign volunteers -such as
George Orwell), or anarcho-
syndicalist groups such as the Durruti Column, the IWA and the
CNT.