Secrets of the Three-Day Moon in Astrology

If you read my last blog post on the Magic of Triplicity Rulers in Astrology, then you’ll recall our introduction to Dorotheus of Sidon, the first-century astrologer whom A. Wasserstein, reviewing David Pingree’s 1976 translation of Carmen Astrologicum, called “immensely influential among Persian, Arabic and Byzantine astrologers of late antiquity and the middle ages” (1). While Ben Dykes advances an argument for the writing of Carmen in the early second century, we can generally assume that Dorotheus’ text was at least in circulation at the time that the famous astronomer, Claudius Ptolemy, was observing the heavens.

Ptolemy’s Tetrabiblos is widely regarded as one of the most influential — if not the most influential — text in the history of Western astrology. Alongside the Almagest and the pseudonymous Centiloquium, these texts contributed to the standard corpus of astrological learning in the Medieval academy, supplemented by Aristotelian and Galenic material. Mark Riley makes an interesting observation concerning Ptolemy’s astrological writing:

“Reviewing…the differences between Ptolemy on the one hand and Dorotheus, Valens, Haphaistion, and Firmicus on the other, one can clearly see the great astronomer’s detachment from the professional concerns of the typical astrologer and his emphasis on the theoretical and universal aspects of…