By the time Israel appeared on the stage of the ancient Near East, civilization and the patterns of empires and of the larger shared culture of the Levant were already well established. Before the end of the fourth millennium BCE, full urbanization had developed in the great river valleys of Egypt and Mesopotamia. The development of sophisticated technology to exploit the flooding of the Nile and to channel the waters of the Euphrates and Tigris enabled the production of regular food supplies and led to regional hegemonies. In Egypt, oriented about the south‐to‐north direction of the Nile's flow, this culminated in the unification of Upper (southern) and Lower (northern) Egypt, at the onset of the Early Dynastic Period toward the end of the fourth millennium. In southern Mesopotamia the kings of Sumer ruled that region from a succession of dominant city‐states beginning at about the same time.