Trotsky and Lenin were central to Russia's Bolshevik Revolution of 1917 and the early Communist International, but had once been fierce adversaries in the revolutionary socialist movement. Trotsky opposed the proletarian self-activity to what he called substitutionism—perhaps an unfair characterization of Lenin's standpoint, but an astonishing forecast of the Stalinist future of the USSR. Yet the perspectives of Lenin and Trotsky converged in 1917, and in 1922 they also came to an agreement in opposing bureaucratic developments associated with Stalin. After Lenin's death, Stalin advanced a rigid variant of "Leninism," which diverged from Lenin's more open and democratic approach (explicated, for example, by Lenin's widow N.K. Krupskaya). Efforts by Trotsky, with others who had been close to Lenin, to resist authoritarian and bureaucratic developments were defeated by Stalin's regime. Expelled from the USSR, Trotsky defended perspectives he had shared with Lenin, until his own death in 1940.