The son of a mapmaker, Fer turned the family business into a flourishing map publishing company in Paris and was appointed geographer to the French dauphin. This map, printed in the last year of Fers life, credits a number of Jesuits, including Pedro Páez and Jerónimo Lobo, for its geographic information. The sources of the Blue Nile are called 'les yeux du Nil' (the eyes of the Nile), probably based on Lobos descriptions of the two springs, and they are shown on or in a mountain. The White Nile is barely represented.