Sumer
Sumer () is the earliest known civilization in the historical region of southern Mesopotamia, modern-day southern Iraq, during the Chalcolithic and Early Bronze ages, and one of the first civilizations in the world along with Ancient Egypt and the Indus Valley. Living along the valleys of the Tigris and Euphrates, Sumerian farmers were able to grow an abundance of grain and other crops, the surplus of which enabled them to settle in one place. Prehistoric proto-writing dates back before 3000 BC. The earliest texts, from c. 3300 BC, come from the cities of Uruk and Jemdet Nasr; early cuneiform script emerged around 3000 BC.
State (polity)
Mesopotamia is generally considered to be the location of the earliest civilization or complex society, meaning that it contained cities, full-time division of labor, social concentration of wealth into capital, unequal distribution of wealth, ruling classes, community ties based on residency rather than kinship, long distance trade, monumental architecture, standardized forms of art and culture, writing, and mathematics and science. It was the world's first literate civilization, and formed the first sets of written laws.