Joseph Stalin was politically ambitious and climbed the ranks to become secretary general of the Central Committee of the Communist Party in 1922. After the death of Lenin, a power struggle occurred over who would be the next party leader. Joseph Stalin claimed power and became dictator of the Soviet Union.
Stalin's collectivization of Soviet farms drew upon the ideology of Marxism. The Five-Year Plans was put in place to direct economic and industrial output. Those not willing to go along with his collectivization plan were executed or sent to Gulags, prisons that utilized harsh forced labor programs. In 1936, Stalin began the ''Great Purge,'' which targeted those he considered a threat to him, and his ideas. Over 700,000 are believed to have been put to death, as a result of the purge. By 1939, Stalin expanded the Soviet Empire when he agreed to a nonaggression pact with Hitler. The pact with Germany allowed him to invade several eastern European countries the Russian Empire had lost after WWI. Lithuania, Estonia, Finland, and Latvia were all annexed, or invaded by the Soviet Union in the 1930s and 1940s.