The bourgeoisie is a social class of business owners and merchants that emerged in the Late Middle Ages, originally as a "middle class" between peasantry and aristocracy. The term "bourgeoisie" usually refers to the ruling upper class of a capitalist society. In Marxist theory, the bourgeoisie plays a heroic role by revolutionizing industry and modernizing society, but it also seeks to monopolize the benefits of this modernization by exploiting the propertyless proletariat and thereby creating revolutionary tensions. The term "bourgeoisie" is often used to denote the middle classes, but in fact, the French term encompasses both the upper and middle economic classes.