Soviet control of the Eastern Bloc was first tested by the 1948 Czechoslovak coup d'état and the Tito–Stalin split over the direction of the People's Federal Republic of Yugoslavia, the Chinese Communist Revolution (1949) and Chinese participation in the Korean War. After Stalin's death in 1953, the Korean War ceased with the 1954 Geneva Conference. In Europe, anti-Soviet sentiment provoked the East German uprising of 1953. The break-up of the Eastern Bloc is often attributed to Nikita Khrushchev's anti-Stalinist speech "On the Cult of Personality and Its Consequences" in 1956. This speech was a factor in the Hungarian Revolution of 1956, which the Soviet Union suppressed. The Sino–Soviet split gave North Korea and North Vietnam more independence from both and facilitated the Albanian–Soviet split. The Cuban Missile Crisis preserved the Cuban Revolution from rollback by the United States but Fidel Castro became increasingly independent of Soviet influence afterwards, most notably during the 1975 Cuban intervention in Angola. In 1975, the communist victory in former French Indochina following the end of the Vietnam War gave the Eastern Bloc renewed confidence after it had been frayed by Soviet leader Leonid Brezhnev's 1968 invasion of Czechoslovakia to suppress the Prague Spring. This led to the People's Republic of Albania withdrawing from the Warsaw Pact, briefly aligning with Mao Zedong's China until the Sino-Albanian split.