<P> (an outlying city in northern Mesopotamia) </P> <P> Apart from Mari, which lies full 330 kilometres (205 miles) north - west of Agade, but which is credited in the king list as having "exercised kingship" in the Early Dynastic II period, and Nagar, an outpost, these cities are all in the Euphrates - Tigris alluvial plain, south of Baghdad in what are now the Bābil, Diyala, Wāsit, Dhi Qar, Basra, Al - Muthannā and Al - Qādisiyyah governorates of Iraq . </P> <P> The Sumerian city - states rose to power during the prehistoric Ubaid and Uruk periods . Sumerian written history reaches back to the 27th century BC and before, but the historical record remains obscure until the Early Dynastic III period, c. the 23rd century BC, when a now deciphered syllabary writing system was developed, which has allowed archaeologists to read contemporary records and inscriptions . Classical Sumer ends with the rise of the Akkadian Empire in the 23rd century BC . Following the Gutian period, there was a brief Sumerian Renaissance in the 21st century BC, cut short in the 20th century BC by invasions by the Amorites . The Amorite "dynasty of Isin" persisted until c. 1700 BC, when Mesopotamia was united under Babylonian rule . The Sumerians were eventually absorbed into the Akkadian (Assyro - Babylonian) population . </P> <Ul> <Li> Ubaid period: 6500--4100 BC (Pottery Neolithic to Chalcolithic) </Li> <Li> Uruk period: 4100--2900 BC (Late Chalcolithic to Early Bronze Age I) <Ul> <Li> Uruk XIV - V: 4100--3300 BC </Li> <Li> Uruk IV period: 3300--3100 BC </Li> <Li> Jemdet Nasr period (Uruk III): 3100--2900 BC </Li> </Ul> </Li> <Li> Early Dynastic period (Early Bronze Age II - IV) <Ul> <Li> Early Dynastic I period: 2900--2800 BC </Li> <Li> Early Dynastic II period: 2800--2600 BC (Gilgamesh) </Li> <Li> Early Dynastic IIIa period: 2600--2500 BC </Li> <Li> Early Dynastic IIIb period: c. 2500--2334 BC </Li> </Ul> </Li> <Li> Akkadian Empire period: c. 2334--2218 BC (Sargon) </Li> <Li> Gutian period: c. 2218--2047 BC (Early Bronze Age IV) </Li> <Li> Ur III period: c. 2047--1940 BC </Li> </Ul>

When did the first city states arise in sumer