At the beginning of the third millennium BC, the Ninevite V culture flourished in Upper Mesopotamia and the Middle Euphrates River region. It extended from Yorghan Tepe in the east to the Khabur Triangle in the west. Ninevite V was contemporary with ED I and marked an important step in the urbanization of the region. The period seems to have experienced a phase of decentralization, as reflected by the absence of large monumental buildings and complex administrative systems similar to what had existed at the end of the fourth millennium BC.