The first civilization to develop in Mesopotamia is widely recognized as the Sumerians. Emerging around 4500 BCE in the southern region of Mesopotamia (modern-day Iraq), the Sumerians are credited with significant advancements, including the creation of one of the earliest writing systems, cuneiform, as well as complex city-states such as Ur and Uruk. They contributed to various fields including mathematics, astronomy, and literature. Their innovations laid the groundwork for future civilizations in Mesopotamia and influenced cultures well beyond the region.