Leon Trotsky was a Russian revolutionary born in 1879 who helped lead the Bolshevik faction of the Russian Social Democratic Party. He played a key role in the 1917 Russian Revolution and helped Vladimir Lenin seize power, becoming the second most powerful man in the new Soviet government. However, he later fell out of favor with Joseph Stalin and was exiled from the Soviet Union. He spent his final years criticizing Stalin from abroad until being assassinated by a Soviet agent in Mexico in 1940 at the age of 60, showing how completely he had been removed from power by his former ally Stalin.