A cartographical renaissance: the Western recovery of Ptolemy's Geographia, 1397-c.1460

A cartographical renaissance: the Western recovery of Ptolemy's Geographia, 1397-c.1460

Recovery. Like his even more famous treatment of astronomy, Ptolemy's Geographia or Cosmographia (2nd century AD) assembled and synthesized knowledge accumulated over centuries in the classic form in which it would be passed down to later centuries. After being lost to the West for several centuries, the work was rediscovered in the thirteenth century by a Byzantine monk named Maximus Planudes. The original Greek version was brought to Florence by the Byzantine scholar Manuel Chrysoloras in 1397 and translated into Latin by Jacobus Angelus of Scarperia around 1409. It was another half-century or more before the maps were reconstructed to illustrate Ptolemy's text (Image), at the very time when printing itself was being (re-)invented in the West. 

Contents. The Geography consists of three sections, divided among 8 books. Book I is a treatise on cartography, describing the methods used to assemble and arrange Ptolemy's data. From Book II through the beginning of Book VII, a gazetteer provides longitude and latitude values for the world known to the ancient Romans (the "ecumene"). The rest of Book VII provides details on three projections to be used for the construction of a map of the world, varying in complexity and fidelity. Book VIII constitutes an atlas of regional maps. The maps include a recapitulation of some of the values given earlier in the work, which were intended to be used as captions to clarify the map's contents and maintain their accuracy during copying.

Projections. This manuscript map is based on a modified conic projection, the first and simplest method outlined in Ptolemy's Geographia. In this projection, the parallels of latitude (running east and west) are drawn as arcs of circles; but the lines of latitude (running north and south) are straight rather than curved and deflected at the equator. This first projection is simpler to construct than the second and more popular projection (illustrated in the following image) but more distorted and fails to capture the impression of the spherical globe.

Image. A reconstruction of Ptolemy's conic projection. Source: Wikimedia Commons, courtesy Enoch Pratt Free Library (CC BY 4.0 DEED). 

Further Reading:

Gerd Graßhoff, Elisabeth Rinner, and Florian Mittenhuber. 2017. “Of Paths and Places: the Origin of Ptolemy's Geography.” Archive for History of Exact Sciences, 71, 81–101.

Shalev, Zur, Charles Burnett, eds. 2011. Ptolemy's Geography in the Renaissance. London: Warburg Institute. (In Appendix: Latin text of Jacopo Angeli's introduction to his translation of the Geography, with English translation by C. Burnett.)

Commentary. Philipp Nothaft (May-June 2019) and Howard Hotson (January 2024)