Marxism–Leninism is a communist ideology which was the main communist movement throughout the 20th century. Developed by the Bolsheviks, it was the state ideology of the Soviet Union, its satellite states in the Eastern Bloc, and various countries in the Non-Aligned Movement and Third World during the Cold War, as well as the Communist International after Bolshevisation. Today, Marxism–Leninism is the ideology of the ruling parties of China, Cuba, Laos and Vietnam (all one-party 'socialist republics'), as well as many other communist parties, while the state ideology of North Korea is derived from Marxism–Leninism. Marxist–Leninist states are commonly referred to as "communist states" by Western academics.