The sumerian kings each controlled a political region called a

The answer is city-state.

1. In Sumerian city-states, politics and religion were intimately related. The governor was the Prince-priest. the "High priest" or "Patesi", who represented the deity.  The priest administered the government of the city, the income of the temple, led the soldiers, supervised the maintenance of the canals and organized the cult. The temple then played a fundamental role. It was the axis of political, religious and also economic life.

2. With the expansion of the Sumerian cities, the administration becomes more complex and there is a change in the attributes of the Patesi, who will be dedicated exclusively to worship.

3. Military leaders converted into Kings will perform the rest of the functions. These kings will maintain the division of Mesopotamia into small states: each city, was a state in itself, with its own institutions of government, did not depend on a regional or imperial major power.