Leon Trotsky (1879-1940), Russian revolutionary and Communist theorist. He was a leader of the revolution of 1917 and, as Commissar of Foreign Affairs and War, largely created the Red Army. He was assassinated in 1940 while in exile in Mexico. * 2/3/00 Britain refused to give asylum to the exiled Russian revolutionary Leon Trotsky for fear of offending his arch rival Josef Stalin, according to official papers made public