Rise of Sumerian City-States

The Uruk period, spanning roughly 4000 to 3100 BCE and named for the southern Mesopotamian city of Uruk, saw the emergence of the world's first true cities and states in what is often called the urban revolution. Uruk itself grew to an estimated 230 to 250 hectares during its late phase, around 3500 to 3300 BCE, with a population plausibly between 25,000 and 50,000, dwarfing neighboring settlements in a pattern archaeologists term urban macrocephaly. The period introduced irrigated agriculture, the potter's wheel, standardized mud-brick monumental architecture and organized textile production, alongside the earliest known writing system, a proto-cuneiform script that emerged around 3350 to 3200 BCE as an administrative tool for tracking goods and labor rather than as literature. Uruk's culture and material style spread well beyond southern Mesopotamia through colonies and trading posts such as Habuba Kabira in Syria, an expansion that reached from Iran to Anatolia before contracting after about 3300 BCE. The centralized administration, social stratification and long-distance trade networks first established during the Uruk period set the foundational pattern for the rest of Mesopotamian civilization.