Vitruvius, On Architecture 8.2

8.2.6

Haec autem sic fieri testimonio possunt esse capita fluminum, quae orbe terrarum chorographiis picta itemque scripta plurima maximaque inveniuntur egressa ad septentrionem. primumque in India Ganges et Indus ab Caucaso monte oriuntur; Syria Tigris et Euphrates; Asiae item Ponto Borysthenes, Hypanis, Tanais; Colchis Phasis; Gallia Rhodanus; Celtica Rhenus; citra Alpis Timavos et Padus; Italia Tiberis; Maurusia, quam nostri Mauretaniam appellant, ex monte Atlante Dyris, qui ortus ex septentrionali regione progreditur per occidentem ad lacum Eptagonum et mutato nomine dicitur Agger, deinde ex lacu Eptabolo sub montes desertos subterfluens per meridiana loca manat et influit in Paludem quae appellatur, circumcingit Meroen, quod est Aethiopum meridianorum regnum, ab hisque paludibus se circumagens per flumina Astansobam et Astoboam et alia plura pervenit per montes ad cataractam ab eoque se praecipitans per septentrionalem pervenit inter Elephantida et Syenen Thebaicosque in Aegyptum campos et ibi Nilus appellatur.

6. That this is the state of the case may be proved by the sources of rivers, the majority and the longest of which, as drawn and described in geographies of the world, are found to rise in the north. First in India, the Ganges and Indus spring from the Caucasus; in Syria, the Tigris and Euphrates; in Pontus in Asia, the Dnieper, Bug, and Don; in >Colchis, the Phasis; in Gaul, the Rhone; in Celtica, the Rhine; on this side of the Alps, the Timavo and Po; in Italy, the Tiber; in Maurusia, which we call Mauretania, the Dyris, rising in the Atlas range and running westerly to Lake Heptagonus, where it changes its name and is called Agger; then from Lake Heptabolus it runs at the base of barren mountains, flowing southerly and emptying into the marsh called . . . It surrounds Meroë, which is a kingdom in southern Ethiopia, and from the marsh grounds there, winding round by the rivers Astansoba and Astoboa and a great many others, it passes through the mountains to the Cataract, and from there it dashes down, and passes to the north between Elephantis and Syene and the plains of Thebes into Egypt, where it is called the Nile.