Tetrabiblos by Claudius Ptolemy, trans. F.E. Robbins
(Cambridge and London: Harvard University Press, 1998)

Judgment: Necessary for students of astrology.

Ptolemy has been receiving something of a bad reputation in recent years, as criticism of his abilities as a mathematician have joined criticism of him as an astrologer.  In fact he was not an astrologer, but rather a selective reporter of ancient techniques in astrology.  He is also a key source for the tropical zodiac, now standard in Western astrology, which is responsible for the "mismatch" between the signs as used in astrology and the constellations bearing their name.

This book is the Robbins translation of one of Ptolemy's two most important works, the Tetrabiblos or "Four Books" of astrology (the other being his astronomical work).  It seems that in antiquity Ptolemy's astrological work was not very influential.  But he gained fame on account of his astronomy and his (re)introduction to the Latin West in the medieval period.  At the time his allegedly "pure" Greek astrology was preferred by the Latins to the "corrupted" astrology of Arab writers: at the time, invasion of the West by Muslim armies had been underway for quite a while.  An appreciation of astrological technique was layered over by political fears.  But Ptolemy's astrology was (as Holden puts it) "deviant": it resembled only in part the horoscopy practiced by professional astrologers like Dorotheus and Vettius Valens.  The Arabic tradition, as it was later transmitted to the Latin West, was the genuine tradition.

That said, the Tetrabiblos is an important work.  It is one of our earliest (and sometimes the only) sources for clear doctrines about astrometeorology, mundane astrology, predictive techniques, and all major areas of natal astrology.  Compared with the styles and presentation of Dorotheus and Vettius Valens, it is a pleasure to read and thorough.  Later medieval techniques are heavily dependent on Ptolemy: for instance, Bonatti's marriage delineation is basically Ptolemy's with Arabic house delineations grafted onto it.  Ptolemy is also a good source for lists of planetary significations, such as what Mercury-Mars aspects mean for the profession or the personality or one's married life.

One of Ptolemy's contributions to astrology is his attempt to explain planetary effects in scientific terms, that is to say in terms of their elemental qualities (like cold and dry for Saturn).  It is one thing to have in mind a list of attributions or associations for a planet, but another to get a sense of the underlying nature of the planet that makes it do what it does -- say, Saturn's malefic effects on fertility or the personality.  Often these qualities and the underlying planetary nature are useful for an astrologer trying to figure out what an unfamiliar configuration means.

Ptolemy's natal astrology makes extensive use of "universal" or "natural" significators, which is partly to be expected from someone interested in basic planetary qualities.  For Ptolemy, the Sun signifies fathers or the male spouse by nature, on account of the Sun's qualities; therefore a marriage or family delineation will rely heavily on the condition and aspects of the Sun.  Many of Ptolemy's delineations rely almost exclusively on these: Mercury for the rational mind, Venus for love, and so on.  Ptolemy does not pay attention to houses other than the angles, so he does not -- and cannot -- make much use of planetary rulerships in delineation.  Instead, he heads right to the universal significators and their aspects. 

One can see Ptolemy's legacy of universal significators in two important places.  First, in the Reformation astrology of William Lilly, Johannes Schoener, and others who began relying more and more on Ptolemy.  When these astrologers give advice on how to delineate a house, they generally list universal significators first (taking information directly from Ptolemy) and house-specific significators next.  This is the reverse of (but does not contradict) the method generally used in the Greco-Arabic-Latin stream of Western astrology, which begins with planets in the relevant houses and their rulers.  The same goes for the great French astrologer Morinus, who followed medieval and Arabic practice despite his dislike of Arabic astrologers. 

Second, modern astrology has almost given up on house rulership altogether, and now relies almost exclusively on Ptolemaic universal significators, buttressed by versions of New Age, Jungian, and Indian psychology and metaphysics.  This trend is not only an impoverishment of Western astrology (and of Ptolemaic astrology), but a perversion of it.  For example, Ptolemy gave the planets universal rulerships over all manner of phenomena, from nations and cities in mundane astrology, to weather patterns, to professions.  But most modern astrologers use only the personality rulerships, treating the natal chart only as a portrait of the native's subjective mind.  Ancient astrologers treated the ascendant as ruling the body, health, and personality of the native, and only used the Sun and the Moon for specific purposes in character or life delineations.  In modern times, the sun sign and moon signs are treated practically as the end-all be-all of the native's life mission, and the ascendant is relegated to being only a social cloak the native takes on.  The result is that modern astrology is a shorn-down, twisted, and subjectivized version of Ptolemaic and other astrology.

Ptolemy's work must be balanced with and used in conjunction with later astrologers like Abu 'Ali, Morinus, Ibn Ezra, and others.  But he has an important role in the astrological tradition, and this lovely and handsome book repays close study.