Trade routes: Mesopotamia was a crossroads for trade between the East and the West. Control of trade routes was important for economic prosperity, and wars between city-states over these routes were also common.
Political power: The city-states of Mesopotamia were constantly competing for political power. Wars between city-states for control of the region were common.
Religious differences: The people of Mesopotamia practiced a variety of religions. Religious differences between city-states were often a source of conflict, and wars between city-states over religious issues were also common.