Ptolemy's Geography

The Science of the Earth's Surface

Ptolemy, who gave Greek astronomy its final form in the second century A.D., did the same--and more--for geography and cartography. His massive work on the subject, which summed up and criticized the work of earlier writers, offered instruction in laying out maps by three different methods of projection, provided coordinates for some eight thousand places, and treated such basic concepts as geographical latitude and longitude. In Byzantium, in the thirteenth century, Ptolemic maps were reconstructed and attached to Greek manuscripts of the text. And in the fifteenth century, a Latin translation of this text, with maps, proved a sensation in the world of the book. A best seller both in the age of luxurious manuscripts and in that of print, Ptolemy's "Geography" became immensely influential. Columbus-- one of its many readers--found inspiration in Ptolemy's exaggerated value for the size of Asia for his own fateful journey to the west. You can go back and through one of the two other ancient doors: Or you can walk all the way back to the Main Hall.