Scattered through the vast expanse of stone and sand that makes up Egypt's Western Desert are several oases. These islands of green in the midst of the Sahara owe their existence to springs and wells drawing on ancient aquifers. In antiquity, as today, they supported agricultural communities, going back to Neolithic times but expanding greatly in the millennium from the Saite pharaohs to the Roman emperors. New technologies of irrigation and transportation made the oases integral parts of an imperial economy. Amheida, ancient Trimithis, was one of those oasis communities. Located in the...