Hungarian Revolution of 1956: A Revolutionary Headquarters is established in Hungary. Following Imre Nagy's announcement of October 30, banned non-Communist political parties are reformed, and the MDP is replaced by the MSZMP. József Mindszenty is released from prison. The Soviet Politburo makes the decision to crush the Revolution.

The Hungarian Revolution of 1956, also known as the Hungarian Uprising, was an attempted countrywide revolution against the government of the Hungarian People's Republic (1949–1989) and the policies caused by the government's subordination to the Soviet Union (USSR). The uprising lasted 15 days before being crushed by Soviet tanks and troops on 7 November 1956. Thousands were killed or wounded, and nearly a quarter of a million Hungarians fled the country.

Imre Nagy was a Hungarian communist politician who served as Chairman of the Council of Ministers of the Hungarian People's Republic from 1953 to 1955. In 1956 Nagy became leader of the Hungarian Revolution of 1956 against the Soviet-backed government, for which he was sentenced to death and executed two years later. He was not related to previous agrarianist Prime Minister Ferenc Nagy.

The Hungarian Working People's Party was the ruling communist party of Hungary from 1948 to 1956.

The Hungarian Socialist Workers' Party was the ruling Marxist–Leninist party of the Hungarian People's Republic between 1956 and 1989. It was organised from elements of the Hungarian Working People's Party during the Hungarian Revolution of 1956, with János Kádár as general secretary. The party also controlled its armed forces, the Hungarian People's Army.

József Mindszenty was a Hungarian cardinal of the Catholic Church who served as Archbishop of Esztergom and leader of the Catholic Church in Hungary from 1945 to 1973. According to the Encyclopedia Britannica, for five decades "he personified uncompromising opposition to fascism and communism in Hungary".