Pinpointing the sources of the legendary Nile River was a goal that stirred the imagination of travellers, cosmographers and cartographers for centuries. The riddle would not be solved until 1863.

Martin Behaim, Mercator’s forerunner in Germany, put the sources of the Nile in the vast stretches of Ethiopia. Mercator himself preferred to situate them south of the equator, projecting them as being fed by two subequatorial lakes surrounded by a network of mountains. This followed Ptolemy’s conception.

Mercator took great care to represent every segment of the Nile’s course, from its delta divided into seven mouths up to the two lakes where it rises. In order these segments are called Alcair, Apollinis, Syene, Berethis, Sacala and Zoquila. On the branch that flows out of the western lake we find Neli, Zodiata, Ithia, Gorala, Gaida, Chaga and Meraga. On the branch flowing from the eastern lake are Bersera, Haba, Singa, Caigra, Baricia, Ropoga, Uque, Heicer, Buatili, Sesila, Losa, Caba, Girat and Bara. Several of these names are taken from Ptolemy.

When Portuguese mariners began exploring the western coastline of Africa, they proceeded from one cape to the next.

In 1488 Bartolomeu Dias came to a headland swept by ferocious winds. He had reached the most southerly point of the African continent, which he named Cape of Storms. It was rechristened Cape of Good Hope to herald the proximity of the Indies. In 1497 Vasco de Gama would sail all the way around Africa to India.

Below the southern tip of Africa, beyond the Cape of Good Hope, Mercator called a part of the Antarctic continent Psitacorum regio, “Land of the Parrots”.

The islands dotting the Gulf of Arabia, to the east of Africa, are taken from Ptolemy. Mercator provides a detailed representation of Madagascar, whose outline apparently came from Portuguese sources, and a number of neighbouring islands.