Ptolemy, Claudius

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Late-medieval illustration showing the circular movements of the planets as theorized by Claudius Ptolemy. From George Purbach’s Theoreticae Novae Planetarum, 1543. Reproduced by permission of Fortean Picture Library.

Ptolemy, Claudius

(religion, spiritualism, and occult)

Claudius Ptolemy (100–178), sometimes called the father of Western astrology, was a Greek astronomer and astrologer who lived in Alexandria, Egypt. Ptolemy was a highly learned individual, with a broad grasp of geography, mathematics, astronomy, and music. His account of the motions of the planets, which placed Earth as the stable center around which the Sun, stars, and planets revolved, was generally accepted until the time of the Copernican revolution.

In his classic astrological work, the Tetrabiblos, Ptolemy attempted to compile the astrological knowledge of his predecessors and systematize it into a unified discipline. He also offered a theory of astrological influence in terms of the science of his day. Despite the shortcomings of his work, Ptolemy’s organization of the body of diverse information into a coherent whole made him the most influential single astrologer in Western history.


Brau, Jean-Louis, Helen Weaver, and Allan Edmands. Larousse Encyclopedia of Astrology. New York: New American Library, 1980.
DeVore, Nicholas. Encyclopedia of Astrology. New York: Philosophical Library, 1948.