MORE ANCIENT SOURCES
Adamnanus, De locis sanctis, II, 30:28 (ca. 670 A.D.)
The city of Alexandria which has beside it the mouth of the Nile called the Canopic Mouth, forms the boundary between Asia (including Egypt) and Lybia. The Egyptians have constructed high banks along the edge of the Nile, on account of the floods it causes. Indeed if they were to neglect this precaution, and allowed the banks to be overflowed, the effect would be that the low-lying fields would not be watered, but rather that they, and anything living on them, would be blotted out. Holy Arculf often crossed the river by boat when travelling about Egypt, and he says that because of this risk many of those who inhabit the plains of Egypt live in houses supported by scaffolds above the water.