The Sino-Soviet split (1956–1966) was the breaking of political relations between the People's Republic of China (PRC) and the Union of Soviet Socialist Republics (USSR), caused by doctrinal divergences that arose from their different interpretations and practical applications of Marxism–Leninism, as influenced by their respective geopolitics during the Cold War (1945–1991).[2] In the late 1950s and early 1960s, Sino–Soviet debates about the interpretation of orthodox Marxism became specific disputes about the USSR's policies of national de-Stalinization and international peaceful coexistence with the Western world, which Mao decried as Marxist revisionism.