Jemdet Nasr
The Jemdet Nasr period, named after the type-site Jemdet Nasr, is generally dated to 3100–2900 BC. It was first distinguished on the basis of distinctive painted monochrome and polychrome pottery with geometric and figurative designs. The cuneiform writing system that had been developed during the preceding Uruk period was further refined. While the language in which these tablets were written cannot be identified with certainty for this period, it is thought to be Sumerian. The texts deal with administrative matters like the rationing of foodstuffs or lists of objects or animals. Settlements during this period were highly organized around a central building that controlled all aspects of society. The economy focused on local agricultural production and sheep-and-goat pastoralism. The homogeneity of the Jemdet Nasr period across a large area of southern Mesopotamia indicates intensive contacts and trade between settlements. This is strengthened by the find of a sealing at Jemdet Nasr that lists a number of cities that can be identified, including Ur, Uruk and Larsa.