3000 BCE - 2400 BCE. The Early Dynastic period in Mesopotamia marks the rise of powerful city-states like Ur and Uruk. During this era, rulers such as Gilgamesh emerged, and the foundations of what would later become sophisticated law systems and religious structures were established.This period's mythology included stories of gods and demigods, with creatures like the Lamassu, a protective deity with a human head and bull's body, symbolizing power and protection.