Hungarian–Soviet relations were characterized by political, economic, and cultural interventions by the Soviet Union in internal Hungarian politics for 45 years, the length of the Cold War. Hungary became a member of the Warsaw Pact in 1955; since the end of World War II, Russian troops were stationed in the country, intervening at the time of the Hungarian Revolution of 1956. Starting in March 1990, the Soviet Army began leaving Hungary, with the last troops being withdrawn on June 19, 1991.