The Great Purge or the Great Terror (Большой террор), also known as the Year of '37 (37-й год) and the Yezhovshchina ('period of Yezhov'), was Soviet General Secretary Joseph Stalin's campaign to solidify his power over the Communist Party of the Soviet Union and the state; the purges were also designed to remove the remaining influence of Leon Trotsky as well as other prominent political rivals within the party. It occurred from August 1936 to March 1938.
Following the death of Vladimir Lenin in 1924, a power vacuum opened in the Communist Party, the ruling party in the Soviet Union (USSR). Various established figures in Lenin's government attempted to succeed him. Joseph Stalin, the party's General Secretary, outmaneuvered political opponents and ultimately gained control of the party by 1928. Initially, Stalin's leadership was widely accepted; his main political adversary Trotsky was forced into exile in 1929, and the doctrine of "socialism in one country" became enshrined party policy. However, by the early 1930s, party officials began losing faith in his leadership following the human cost of the first five-year plan and the collectivization of agriculture. By 1934, several of Stalin's rivals, such as Trotsky, began calling for Stalin's removal and attempted to break his influence over the party.
In this atmosphere of doubt and suspicion, a popular high-ranking official, Sergei Kirov, was assassinated. His death led to an investigation that revealed a network of party members supposedly working against Stalin, including several of Stalin's rivals. Many of those arrested after Kirov's assassination also confessed plans to kill Stalin himself, including high-ranking party officials. The validity of these claims is still debated by historians, but there is consensus that Kirov's death was the flashpoint where Stalin took action and began the purges.
By 1936, Stalin's measures to strengthen his grip on power reached their peak. The perceived risk of losing his position and the potential return of Trotsky drove him into authorizing the Great Purge.