In 1845 Marx was ordered to leave Paris because of his revolutionary activities. He settled in Brussels and began the work of organizing and directing a network of revolutionary groups, called Communist Correspondence Committees, in a number of European cities. In connection with the consolidation of these committees in 1847 to form the Communist League, Marx and Engels were commissioned to formulate a statement of principles. The programme they submitted, known throughout the world as the Communist Manifesto, was the first systematic statement of modern socialist doctrine and was written by Marx, partly on the basis of a draft prepared by Engels. The central propositions of the Manifesto, contributed by Marx, embody the theory, later explicitly formulated in his Critique of Political Economy (1859), called the materialist conception of history, or historical materialism. These propositions are that in every historical epoch the prevailing economic system by which the necessities of life are produced 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 the exploiting and the exploited, that is, between the ruling and the oppressed social classes. From these premises, Marx drew the conclusion in the Manifesto that the capitalist class would be overthrown and that it would be eliminated by a worldwide working-class revolution and replaced by a classless society. The Manifesto influenced all subsequent communist literature and revolutionary thought generally; it has been translated into many languages and published in hundreds of millions of copies.