Which ancient civilization was made up of city states?

The ancient civilization of Sumer, located in Mesopotamia (modern-day Iraq), was made up of city-states. Each city-state, such as Ur, Uruk, and Lagash, operated independently with its own government and deities, often engaging in trade and competition with one another. This structure allowed for the development of distinct cultures and innovations within each city-state while contributing to the overall advancement of Sumerian society.