The best documentary evidence indicates that, sometime in the second century B.C.E., Hellenistic astrology burst onto the scene like a nova. Within the short span of a hundred years or so, the rather minimal legacy from Babylonia and Egypt was totally transformed and an entirely new body of astrological doctrine came to light. This fervent period of intense astrological concentration resulted in a veritable cornucopia of new astrological concepts and practices. These included such basic matters as aspects, the concept of rulership, the meanings of the houses, transits to the natal chart, and synastry, all of which have remained defining for Western astrology to this day, as well as an abundance of other concepts and techniques that did not make it into the twentieth century. This is why we can say that Hellenistic astrology effectively constitutes the real birth of Western astrology.
However, there was no real superfluity here. Inspired by an entirely new cosmological vision, which they captured in the form of an intricate and rigorous metaphysical system, the founders of Hellenistic astrology generated just those concepts and techniques necessary to satisfy the requirements of their new theoretical framework. This is a stunning achievement; for whereas Jones and Rudhyar accomplished a far-reaching re-conceptualization of astrology within a comparable span of time, they were able to take the traditional concepts and techniques as "givens," though by that time these were mere embers.
The lineage recorded by Firmicus Maternus credits one Hermes Trismegistus with the founding of the Hellenistic astrological tradition. Accordingly, we will refer to this original system as "The System of Hermes," regardless of whether a man going by this name was the actual founder or not. As it turns out, this designation is appropriate for a number of other reasons as well. This is the system that we have restored to its original form, and which we would now like to recommend to students of modern astrology.
The most common reaction of those who have undertaken the study of Hellenistic astrology is that it makes sense. This is true of the way in which its concepts and techniques are linked together into a coherent system, in its assignment of meaning to celestial phenomena, in its suggestive technical terminology, and in its methodical and readily learnable approach to chart reading.
More than any other type of astrology, the Hellenistic System of Hermes unites theory and practice. Its concepts and techniques were introduced to meet the very specific requirements of a timeless cosmological theory. The theory is fully embedded in the practice, which in return articulates and coordinates the various components of this theory. Thus, it is a coherent and self-contained system.
Hellenistic astrology was practiced for many centuries. It was also at the core of Medieval astrology, which likewise was practiced for centuries. This is far longer than modern astrology, which is effectively a product of the twentieth century. So we must assume that Hellenistic and Medieval astrologers found an ongoing validation for their practice at least as compelling as that of modern astrologers.
Most of the astrological concepts and techniques used to this day were introduced during the Hellenistic era, including such fundamentals as houses, rulership, the Lot of Fortune, and aspects, and central timing procedures such as primary directions, progressions, and transits. Many outstanding issues in modern astrology can almost immediately be cleared up by studying these concepts and techniques in their original form. Among these are the problem of house division, the enigma of the concrete meanings assigned to the houses, what to do with the Lot of Fortune, and ambiguities in the precise delineation of planetary combinations.
The System of Hermes contains a vast reservoir of concepts and techniques that modern astrologers have never had the opportunity to study until now. All of them originally had a systematic connection to those still in use. Their examination and evaluation could well keep enterprising astrologers busy for decades to come.
The study of Hellenistic astrology also has great potential for rectifying certain mistakes that have entered astrology simply due to errors in the transmission of this doctrine. Since the bulk of these errors occurred during the Medieval period, modern practitioners of Medieval astrology may also wish to make the study of Hellenistic astrology a high priority.
The theory underlying Hellenistic astrology could help restore confidence in astrology. Because modern science has made the notion of planetary causation implausible, we moderns have a hard time seeing how astrology could “work” without retreating into the mysteries of synchronicity. Hellenistic astrology offers another alternative, one that opens up a view of the cosmos in which astrology is an authentic possibility.