The history of all hitherto existing society is the history of class struggles.
Freeman and slave, patrician and plebeian, lord and surf, guild-master and journeyman, in a word, oppressor and oppressed, stood in constant opposition to one another, carried on an uninterrupted, now hidden, now open fight, a fight that each time ended in a revolutionary reconstitution of society at large, or in common ruin of the contending classes.