Béla Kun (20 February 1886 — 29 August 1938 or 30 November 1939), born Béla Kohn, was a Hungarian revolutionary and politician who de facto led the Hungarian Soviet Republic in 1919. Following the fall of the Hungarian revolution, Kun emigrated to the Soviet Union, where he worked as a functionary in the Communist International bureaucracy. The head of the Crimean Revolutionary Committee since 1920. Organizer and an active participant of the Red Terror in Crimea (1920—1921).
During the Great Purge of the late 1930s, Kun was arrested, interrogated, tried, and executed in quick succession. He was posthumously rehabilitated in 1956, following the death of Joseph Stalin and the critical reassessment of Stalinism.
After World War II the Soviets inaugurated a Communist regime under the leadership of Mátyás Rákosi, one of Kun's few surviving colleagues from the 1919 coup.
More information on the English and Hungarian Wikipedia pages.