Hungarian People's Republic in the context of "Second Hungarian Republic"

The Socialist Federal Republic of Yugoslavia (commonly abbreviated as SFRY or SFR Yugoslavia), known from 1945 to 1963 as the Federal People's Republic of Yugoslavia, commonly referred to as Socialist Yugoslavia or simply Yugoslavia, was a country in Central and Southeast Europe. It was established in 1945, following World War II, and lasted until 1992, dissolving amid the onset of the Yugoslav Wars. Spanning an area of 255,804 square kilometres (98,766 sq mi) in the Balkans, Yugoslavia was bordered by the Adriatic Sea and Italy to the west, Austria and Hungary to the north, Bulgaria and Romania to the east, and Albania and Greece to the south. It was a one-party socialist state and federation governed by the League of Communists of Yugoslavia, and had six constituent republics: Bosnia and Herzegovina, Croatia, Macedonia, Montenegro, Serbia, and Slovenia. Within Serbia was the Yugoslav capital city of Belgrade as well as two autonomous Yugoslav provinces: Kosovo and Vojvodina.

The country emerged as Democratic Federal Yugoslavia on 29 November 1943, during the second session of the Anti-Fascist Council for the National Liberation of Yugoslavia midst World War II in Yugoslavia. Recognised by the Allies of World War II at the Tehran Conference as the legal successor state to Kingdom of Yugoslavia, it was a provisionally governed state formed to unite the Yugoslav resistance movement. Following the country's liberation, King Peter II was deposed, the monarchical rule was ended, and on 29 November 1945, the Federal People's Republic of Yugoslavia was proclaimed. Led by Josip Broz Tito, the new communist government sided with the Eastern Bloc at the beginning of the Cold War but pursued a policy of neutrality following the 1948 Tito–Stalin split; it became a founding member of the Non-Aligned Movement, and transitioned from a command economy to market-based socialism. The country was renamed Socialist Federal Republic of Yugoslavia in 1963.

The Socialist Republic of Romania (Romanian: Republica Socialistă România, RSR) was a communist state that existed officially in Romania from 1947 to 1989 (see Revolutions of 1989). From 1947 to 1965, the state was known as the Romanian People's Republic (Republica Populară Romînă, RPR). The country was an Eastern Bloc state and a member of the Warsaw Pact with a dominant role for the Romanian Communist Party enshrined in its constitutions. Geographically, RSR was bordered by the Black Sea to the east, the Soviet Union (via the Ukrainian and Moldavian SSRs) to the north and east, Hungary and Yugoslavia (via SR Serbia) to the west, and Bulgaria to the south.

As World War II ended, Romania, a former Axis member which had overthrown their pro-Axis government, was occupied by the Soviet Union as the sole representative of the Allies. On 6 March 1945, after mass demonstrations by communist sympathizers and political pressure from the Soviet representative of the Allied Control Commission, a new pro-Soviet government that included members of the previously outlawed Romanian Workers' Party was installed. Gradually, more members of the Workers' Party and communist-aligned parties gained control of the administration and pre-war political leaders were steadily eliminated from political life. In December 1947, King Michael I was forced to abdicate and the People's Republic of Romania was declared.

The Eastern Bloc, also known as the Communist Bloc (Combloc), the Socialist Bloc, the Workers Bloc, and the Soviet Bloc, was an unofficial coalition of Communist states of Central and Eastern Europe, Asia, Africa, and Latin America that were aligned with the Soviet Union and existed during the Cold War (1947–1991). These states followed the ideology of Marxism–Leninism and various types of socialism, in opposition to the capitalist Western Bloc. The Eastern Bloc was often called the "Second World", whereas the term "First World" referred to the Western Bloc and "Third World" referred to the non-aligned countries that were mainly in Africa, Asia, and Latin America but notably also included former pre-1948 Soviet ally Yugoslavia, which was located in Europe.

In Western Europe, the term Eastern Bloc generally referred to the USSR and Central and Eastern European countries in the Comecon (East Germany, Poland, Czechoslovakia, Hungary, Romania, Bulgaria, and Albania). In Asia, the Eastern Bloc comprised Mongolia, Vietnam, Laos, Kampuchea, North Korea, South Yemen and China. In the Americas, the countries aligned with the Soviet Union included Cuba from 1961 and for limited periods Nicaragua and Grenada.

On 20–21 August 1968, the Czechoslovak Socialist Republic was jointly invaded by four Warsaw Pact countries: the Soviet Union, the Polish People's Republic, the People's Republic of Bulgaria, and the Hungarian People's Republic. The invasion stopped Alexander Dubček's Prague Spring liberalisation reforms and strengthened the authoritarian wing of the Communist Party of Czechoslovakia (KSČ).

About 250,000 Warsaw Pact troops (rising afterwards to about 500,000), supported by thousands of tanks and hundreds of aircraft, participated in the overnight operation, which was code-named Operation Danube. The Socialist Republic of Romania and the People's Republic of Albania refused to participate. East German forces, except for a small number of specialists, were ordered by Moscow not to cross the Czechoslovak border just hours before the invasion, because of fears of greater resistance if German troops were involved, due to public perception of the previous German occupation three decades earlier. 137 Czechoslovaks were killed and 500 seriously wounded during the occupation.

The Hungarian Revolution of 1956 (23 October – 4 November 1956; Hungarian: 1956-os forradalom), 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 (outside of Budapest firefights lasted until at least 12 November 1956). Thousands were killed or wounded, and nearly a quarter of a million Hungarians fled the country.

The Hungarian Revolution began on 23 October 1956 in Budapest when university students appealed to the civil populace to join them at the Hungarian Parliament Building to protest against the USSR's geopolitical domination of Hungary through the Stalinist government of Mátyás Rákosi. A delegation of students entered the building of Magyar Rádió to broadcast their sixteen demands for political and economic reforms to civil society, but were detained by security guards. When the student protestors outside the radio building demanded the release of their delegation, a group of police from the ÁVH (State Protection Authority) fatally shot several of the students.