Around 3100 B.C. Memphis was chosen for its strategic importance to be the first capital of a recently united Egypt. A. River-based trade from northern Egypt and imported goods going south all passed through the Memphis region, making Memphis an ideal location for controlling trade. B. Recent geological surveys suggest that the topographical features of the Memphis region made it particularly well-suited for controlling communications and trade. C. The rulers of unified Egypt enjoyed a monopoly over foreign trade because all such trade was required to go through the Wadi Digla, to which the rulers controlled all access. D. After Memphis became the capital city, river-based trade along the Nile gained in importance, while land-based desert trade declined in importance. E. The Nile, despite a constriction of its valley near Memphis, was the most advantageous route for communication and travel once the floodplain had begun to rise. F. While the location of Memphis was agriculturally favorable, it was particularly attractive because it enabled Egypt's rulers to control trade moving through the desert from the Near East.