In the 19th century, The Communist Manifesto (1848), by Karl Marx and Friedrich Engels, called for the international political unification of the European working classes in order to achieve a Communist revolution; and proposed that, because the socio-economic organization of communism was of a higher form than that of capitalism, a workers' revolution would first occur in the economically advanced, industrialized countries. Marxist social democracy was strongest in Germany throughout the 19th century, and the Social Democratic Party of Germany inspired Lenin and other Russian Marxists.[3]