Why Cities Need Surplus

The fundamental requirement for city life was surplus agriculture. Irrigation channels transformed flood-prone land between the Tigris and Euphrates into the ancient world's most productive farmland. One farmer could produce enough for several non-farmers, freeing people to become artisans and soldiers.

Sumerian farmers produced roughly three times more grain than their families needed. That surplus fed priests, soldiers, and scribes who never touched a plow. Without stored grain, no city survived failed harvests.