A general map of Mesopotamia and its neighbouring territories
which roughly covers the period from 2000-1600 BC reveals the
concentration of city states in Sumer, in the south.
This is where the first true city states arose, although the
cities of northern Mesopotamia and Syria were roughly
contemporaneous. However, the latter remained relatively minor
states with a less intensive level of development until the collapse
of Sumerian civilisation. In the ensuing power vacuum, cities such
as Ashur (one of the three main Assyrian cities), and Ebla and
Babylon (both Amorite cities) quickly grew in wealth and strength.
Shubat-Enlil, in the Khabur river valley in northern Mesopotamia
was the rapidly developed capital of Shamshi-Adad's kingdom of Upper
Mesopotamia in the nineteenth century BC. Before that it had been a
Halaf Culture town and the capital of a minor state called Apum.