Marx, Karl (1818-1883), German political philosopher and revolutionist, cofounder with Friedrich Engels of scientific socialism (modern communism) and, as such, one of the most influential thinkers of all times. Marx was born in Trier. In 1842 he became editor of the Cologne newspaper Rheinische Zeitung. When Marx criticized contemporary political and social conditions, the authorities closed the paper. Marx then went to Paris. In 1844 Marx and Engels began a collaboration to elucidate systematically the theoretical principles of communism and to organize an international working-class movement dedicated to those principles.

In 1845 Marx settled in Brussels and began organizing and directing a network of revolutionary groups. In 1847 he and Engels submitted a statement of principles known as the Communist Manifesto, the first systematic statement of modern socialist doctrine. The Manifesto's propositions are that in every historical epoch the prevailing economic system determines the form of societal organization and the political and intellectual history of the epoch; and that the history of society is a history of struggles between ruling and oppressed social classes. Marx concluded that the capitalist class would be overthrown by a working-class revolution and replaced by a classless society.

In 1848 revolutions occurred in France and Germany. The Belgian government, fearful that the revolutionary tide would engulf Belgium, banished Marx. He went to Paris and the Rhineland, where he encountered problems with the authorities. He left for London in 1849 and spent the remainder of his life there, devoting himself to study and writing and to building an international communist movement. During this period he wrote a number of works that are regarded as classics of communist theory, including his greatest work, Das Kapital (volume 1, 1867; volume 2, 1885; volume 3, 1894), a systematic and historical analysis of the economy of the capitalist system of society.

In 1864, when the First International was established in London, Marx made the inaugural address, wrote the statutes of the International, and directed the work of its governing body. The last eight years of his life were marked by an incessant struggle with physical ailments that impeded his political and literary labors. Marx's influence during his lifetime was not great. After his death it increased with the growth of the labor movement. His doctrines were revived in the 20th century by Russian revolutionary Vladimir Ilich Lenin, who developed and applied them