Grigory Yevseyevich Zinoviev, (September 23, 1883 - August 25, 1936) Soviet communist. Zinoviev was member of the Bolshevik party from its creation in 1903, and one of Lenin's closest associates. Returned to Russia in 1917 in the sealed train with Lenin, but later lost favor due to his opposition to the Bolshevik seizure of power in October. When it came to real action, however, Zinoviev shrank from the proposed revolutionary coup and on 10 October 1917 he and Kamenev were the only two Central Committee members to vote against Lenin on the issue of staging the armed move which was to place the Bolsheviks in power. Zinoviev took virtually no part in the actual October revolution and Lenin did not forget his faint-heartedness. He soon returned to the fold, and became a member of the Politburo from 1919, as well as the head of the Comintern. He was one of the most powerful figures in the USSR after Lenin's death in 1924. Initially he, along with his close associate Lev Kamenev formed part of a ruling triumvirate in the Communist Party with Josef Stalin, and played a key role in the marginalising of Leon Trotsky. Stalin began to sideline Zinoviev once he had consolidated his powerbase in the party , and, along with Kamenev was generally removed from most positions of influence within the party and government.
As part of Stalin's purges, Zinoviev and Kamenev were arrested in 1935 and charged with being involved in the assassination of Sergei Kirov. Found guilty, Zinoviev was sentenced to 10 years' imprisonment. It is likely that Stalin had actually ordered the assassination of Kirov. The following year he was charged with forming a terrorist organization to kill Joseph Stalin and other leaders of the government. Along with Lev Kamenev, he was found guilty and executed on August 25th, 1936.