The Sumerian city-states in 2500 BC were divided into many independent states each ruled by their own dynasties. During this time period, new cities were emerging throughout the fertile crescent region as Sumerian civilization expanded. Overall, Sumerian society was decentralized with political power distributed among competing dynasties ruling separate city-states across the lower Mesopotamia area in 2500 BC.

1. 2,500 BC
• 2500 BC: Many Sumerians city-states under the rule of dynasties
• 2500 BC: new cities were arising all over the fertile crescent