Leon Davidovich Trotsky ( 1879 - 1940 in) was a Russian revolutionary and political theoretician. He was of Jewish-Ukrainian descent. After leading the Red Army in the Russian Civil War.  When Vladimir Lenin died, Trotsky became involved in a power struggle with Joseph Stalin for the leadership of the party. He lost, and Stalin came to power. He had to leave Russia because of Stalin, who was now his own enemy and wanted to harm Trotsky. In 1938 Trotsky founded the Fourth International. Stalin had one of his spies, Spaniard Ramón Mercarder, stab Trotsky to death in Mexico in 1940.