The Maya also developed social class system which was a well-ordered and carried on trade throughout a network of cities that went as far south as Panama and as far north as Central Mexico.

UNESCO: Culture

Inflation destroys the middle class, the social equivalent of a levee system, and then the floods come.

FORBES: The Inflation Intifada: Hunger And Revolution In The Third World

The medieval and early modern social system was based on ideas of people being born into a certain social class and achieving maximum happiness by accepting the privileges and duties of their station.

FORBES: Hipster Tax Has Historical Precedent