(1886–1939?), Hungarian Communist leader, who headed the Hungarian Soviet Republic in 1919.

Kun was born in Szilágy-Cseh, Transylvania, on Feb. 20, 1886, espoused Marxian socialism in his youth, and later joined the Hungarian Social Democratic party. Upon the outbreak of World War I he was drafted into the Austro-Hungarian army; he was captured by Russian troops in 1915 and sent to a prison camp in Siberia. Kun spent the ensuing two years disseminating revolutionary socialist propaganda among his fellow prisoners. After the Bolshevik Revolution of 1917, Kun was allowed to go to Moscow, where he became the leader of a group of Hungarian Communists. One year later he led this group to Budapest and launched a movement to overthrow the recently established Hungarian Democratic Republic. In February 1919 he was arrested by the government and imprisoned, but in the following month the head of the government, Count Mihály Károlyi, realizing his regime was faced with imminent collapse, handed the governmental power over to Kun and the Communists, who immediately proclaimed the establishment of a Hungarian Soviet Republic. Kun launched a military offensive against the Czech armies then poised on the Hungarian border, and after winning a series of victories he set up a soviet republic in Slovakia in June 1919. An invading Romanian army, however, soon forced him to withdraw.

Meanwhile the domestic situation in Hungary had deteriorated as a result of Kun’s policies, and when the Romanian army advanced to the outskirts of Budapest, the Hungarian Soviet Republic collapsed. Kun fled to Vienna and from there to the Soviet Union in 1920. Welcomed by Soviet leaders, he was given an important role in the third Communist International (q.v.), in which he attempted to foment revolution in Europe. After the 1920s, however, little is known of his activities. He was later charged with Trotskyism and executed in one of Joseph Stalin’s purges, reportedly on Nov. 30, 1939.