Pingree, D., 1997, From Astral Omens to Astrology - From Babylon to Bīkāner, 21-22.
The science of astrology was developed in, most probably, the late 2nd or early 1st century B.C. as a mean to predict, from horoscopic themata draw up for the moment of an individual’s birth (or conception), the fate of that native. This form of astrology, called genethlialogy, is rooted in Aristotelian physics and Hellenistic astronomy, but also borrowed much from Mesopotamia and some elements from Egypt as well as developing many theories of its own. The adaptation of this form of astrology to determine the best time for initiating actions is termed catarchic astrology. These are the two main forms of astrology known in the West; interrogational astrology was developed in India in the 2nd and 3rd centuries A.D. on the basis of Greek catarchic astrology, and historical astrology in Sasanian Iran in perhaps the 5th or 6th century A.D. on the basis of continuous forms of Greek genethlialogy All of these types of astrology depend on the notion that the planets, in their eternal rotations about the earth, transmit motion (change) to the four elements and to the assemblages of elements, animate and inanimate, in the sublunar world. This theory is completely different from that of celestial omens, in which the gods, whose physical manifestations are the constellations and planets, send messages concerning their intentions regarding kings and countries by means of celestial phenomena. That these divine intentions con be altered by the use of propitiatory rituals (namburhis in Mesopotamia, śāntis in India) emphasizes the fundamental conceptual difference between omens and astrology.
Pingree, D., 1997, From Astral Omens to Astrology - From Babylon to Bīkāner. Roma: Istituto Italiano per L'Africa e L'Oriente.
