Maps of Africa included in Cosmographia (“guide to geography” in the original Greek, here translated into Latin) (Rome: Petrus de Turre publisher, 1490) by Claudius Ptolemaeus (AD 90-168), opening: 15 1/8 x 22 ½ in., Walters Art Museum 91.1013. Location: Manuscript and Rare Book Collection (not on view).

Generally speaking there were few advances in mapping the known world made by Europeans in the Middle Ages, so that in the early Renaissance of the 1400s, the most advanced maps were those created on the basis of the newly retrieved writings of Claudius Ptolemaeus (AD 90-168), known today simply as Ptolemy. In the first place, he understood the world to be a globe (versus the flat pie-shaped maps of the Middle Ages) so drawing a map on a flat surface required accommodation, as can be seen in the first map, showing the whole world, as far as was known to educated people in the Roman empire of the second century. Problems that pertain to the knowledge about Africa result primarily from the lack of information about the southern part of the continent: it is a blob of unknown dimensions inhabited by various groups of “Ethiopians” (Aethiopes, people with skin that seemed to be “burned” black).

Ptolemy speculated that there was a land bridge to Asia (see the rippled line at the bottom of the “world” map. Ptolemy includes too many rivers running through the Sahara; it was hard for someone who had not been there to grasp how dry and vast it was. Looking at the second map, which is of Africa itself, you can pick out the Nile river which is shown rising in the south from two lakes (paludes Nili) is sufficiently close to the real origins of the Nile in Lake Victoria that it must be based on legitimate information. In the detail, you can pick out Alexandria, where Ptolemy lived, at the mouth of the Nile. Cairo was built later and isn’t shown here.