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The Marxist critique of capitalism — developed with Friedrich Engels — was, alongside liberalism and fascism, one of the defining ideological movements of the Twentieth Century. The industrial revolution produced a parallel revolution in political thought. Urbanization and capitalism greatly reshaped society. During this same period, the socialist movement began to form. In the mid-19th century, Marxism was developed, and socialism in general gained increasing popular support, mostly from the urban working class. Without breaking entirely from the past, Marx established principles that would be used by future revolutionaries of the 20th century namely Vladimir Lenin, Mao Zedong, Ho Chi Minh, and Fidel Castro. Though Hegel's philosophy of history is similar to Immanuel Kant's, and Karl Marx's theory of revolution towards the common good is partly based on Kant's view of history—Marx declared that he was turning Hegel's dialectic, which was "standing on its head", "the right side up again". Unlike Marx who believed in historical materialism, Hegel believed in the Phenomenology of Spirit. By the late 19th century, socialism and trade unions were established members of the political landscape. In addition, the various branches of anarchism, with thinkers such as Mikhail Bakunin, Pierre-Joseph Proudhon or Peter Kropotkin, and syndicalism also gained some prominence. In the Anglo-American world, anti-imperialism and pluralism began gaining currency at the turn of the 20th century.

What was one of the defining ideological movements of the Twentieth Century?
The Marxist critique of capitalism