Northern Mesopotamia is made up of hills and plains. The land is quite fertile due to seasonal rains, and the rivers and streams flowing from the mountains. Early settlers farmed the land and used timber, metals and stone from the mountains nearby.
Further north (in Mesopotamia) lay the city of Ashur overlooking an important crossing of the River Tigris. The city dominated the caravans of donkeys carrying metals and rare materials from east and west, and the boats moving to and from the Sumerian cities to the south. As an important trading centre, Ashur had, by 2000 B.C., established commercial colonies in Turkey.
Cloth and tin were exchanged for silver. Records of these activities on clay tablets have been found at a number of sites in Turkey. Deeds were often protected by an envelope of clay on which a summary of the transaction was written and sealed with cylinder seals.
At the end of the nineteenth century B.C. an ambitious soldier called Shamshi-Adad brought Ashur under his control. He established an empire which stretched across north Mesopotamia. Around 1780 B.C. Shamshi-Adad died and his sons lacked their father's abilities. The empire collapsed and Ashur and the north was now open to attack. When it came it was from the south.
Hollow ways, also called linear ways or sunken lanes, are broad and shallow linear depressions in the landscape, thought to be formed by the continuous passage of the human and animal traffic. They occur on the dry farming plains of the northern Mesopotamia and elsewhere in the Middle East, and are generally 60-120 m wide and 0.50-1.5 m deep. In spite of their size, these hollow ways can be difficult to detect on the ground. In northern Mesopotamia, their visibility can be explained differently in different seasons.
From the end of the 5th to the end of the 3rd millennium BC, Northern Mesopotamian civilization experienced cycles of expansion and contraction, in terms of urbanization, political centralization, growth of institutions, and various aspects of economic organization.
The reemergence of social complexity in the later 3rd millennium was not, however, merely a return to an earlier stage. The initial phase (ca. 4400-3400 BC) was geographically uneven and characterized by gradual development.
Although they developed sophisticated productive technologies, particularly in the area of metallurgy, the 4th millennium riverine settlements lacked social institutions capable of counteracting processes of settlement fissioning prior to the Uruk expansion.
The large indigenous settlements that did develop, in particular Tell Brak and Khirbat al-Fakhar, were isolated and heavily primate centers with few scalar intermediaries between themselves (55 ha and 300 ha, respectively) and their village/hamlet neighbors.