ASTROLOGY. When astrology, a product of Hellenistic civilization, appeared at the end of the third century BCE, its origins were ascribed to the revelations of the Egyptian god Hermes (Thoth). However, its practitioners were usually called "Chaldeans," a formula devoid of any actual historical reference to Mesopotamia. Hellenistic astrology was actually a combination of Chaldean and Egyptian astral religion and Greek astronomy and methods of computation. Even though Hellenistic astrology and the astrology of late antiquity took on the features of different local traditions when exported to India, China, or Islamic countries, their basic ingredients are, in all places, Greek science and Chaldean and Egyptian astral lore.

The actual contribution of the latter to Greek astrology is debatable, for the Chaldean and Egyptian traditions were widely divergent on some points. However, the idea of two malefic planets—Mars and Saturn—is genuinely Chaldean; genuinely Egyptian, but no older...