By mid-19th century, capitalism had replaced feudalism in many countries. Together with it the proletariat, the most progressive and consistently revolutionary class whose mission was to put an end to exploitation of man by man and establish a new, communist society, emerged on the historical scene. The proletariat's liberation movement confronted science with the exceptionally important tasks of formulating a scientific theory that would help it accomplish its historic mission and become its ideological weapon in the fight against capitalism, for socialism and communism. Science fulfilled this insistent demand of history: the brilliant leaders of the working class and of all working people, Marx and Engels, evolved Marxism whose component and theoretical foundation is Marxist philosophy, dialectical and historical materialism