Nautilus

Mapping Gay-Friendly Cities Through History

Claudius Ptolemy’s monumental astronomy book, the Almagest, established a unified mathematical framework for computing the positions of the sun, moon, stars, and planets at any time in the past, present, or future. So comprehensive and so compelling was the Earth-centered cosmos it described that the Almagest would remain the final word in astronomy for nearly 1,500 years, until it was finally superseded by the sun-centered system of Copernicus and Kepler. Somewhat less well known is that Ptolemy was also the ancient world’s greatest geographer and its greatest, or at least most well-respected, astrologer. Indeed, Ptolemy’s astrology book, the Tetrabiblos, was still required reading at the University of Bologna when Copernicus studied there a millennium and a half later.

Within the , Ptolemy’s astronomy, astrology, and geography come together in a remarkable discussion of “astral geography.” Ptolemy’s system for linking terrestrial and celestial real estate endowed his astrology with a sense of space as well as time. It also greatly multiplied the number of correspondences to consider. Ptolemy’s resulting astrological world map is a fascinating document of attitudes toward race and ethnicity in the ancient world. For our

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