Leon Trotsky was a key leader of the Russian Revolution. Forced into exile in 1928, Trotsky devoted the rest of his life to fighting the degeneration of the revolution and rise of a new dictatorial regime. Vilified and isolated, he fought an uncompromising battle with the Stalinist bureaucracy, defending the revolutionary and internationalist principles upon which the revolution was based. In 1940, he was murdered by an agent of the Stalinist regime.