This chapter deals with some of the theories about the course of the Nile which were held during the late medieval and early modern period. The idea of writing the paper came from Dr. Mannoni's publication of the mid-fifteenth-century map of Abyssinia called Egyptus Novelo; and that led to an examination of Fra Maura's almost contemporary world-map covering the same region. The maps are of two kinds; those covering the whole of known Africa and those covering only part of it. At or above Assuan the Nile divides into two branches coming from the south-west and south-east respectively: the south-west branch turns to the west, rising in a marsh which is also the source of another river flowing westwards to the Atlantic. The earliest European source of information about the Upper Nile region is contained in 'The Book of Knowledge,' compiled by a Spanish monk soon after 1348.