Marx was expelled from Paris at the end of 1844 and with Engels, moved to Brussels where he remained for the next three years, visiting England where Engels' family had cotton spinning interests in Manchester. While in Brussels Marx devoted himself to an intensive study of history and elaborated what came to be known as the materialist conception of history. At the same time Marx was composing The German Ideology, He also joined the Communist League. This was an organization of German emigre workers with its center in London of which Marx and Engels became the major theoreticians. At a conference of the League in London at the end of 1847 Marx and Engels were commissioned to write a succinct declaration of their position. Scarcely was The Communist Manifesto published than the 1848 wave of revolutions broke out in Europe.
Early in 1848 Marx moved back to Paris when a revolution first broke out and onto Germany where he founded, again in Cologne, the Neu Rheinische Zeitung. The paper supported a radical democratic line against the Prussian autocracy and Marx devoted his main energies to its editorship since the Communist League had been virtually disbanded. Marx's paper was suppressed and he sought refuge in London in May 1849 to begin the "long, sleepless night of exile" that was to last for the rest of his life.
Settling in London, Marx was optimistic about the imminence of a new revolutionary outbreak in Europe. He rejoined the Communist League and wrote two lengthy pamphlets on the 1848 revolution in France and its aftermath, The Class Struggles in France and The 18th Brumaire of Louis Bonaparte. He was soon convinced that "a new revolution is possible only in consequence of a new crisis" and then devoted himself to the study of political economy in order to determine the causes and conditions of this crisis.