" The basic thought running through the Manifesto - that economic production and the structure of society of every historical epoch necessarily arising therefrom constitute the foundation for the political and intellectual history of that epoch; that consequently (ever since the dissolution of the primeval communal ownership of land) all history has been a history of class struggles, of struggles between exploited and exploiting, between dominated and dominating classes at various stages of social development; that this struggle, however, has now reached a stage where the exploited and the oppressed class (the proletariat) can no longer emancipate itself from the class which exploits and oppresses it (the bourgeoisie), without at the same time forever freeing the whole society from exploitation, oppression and class struggles - this basic thought belongs solely and exclusively to Marx. "

― Friedrich Engels , The Communist Manifesto