Nature and significance

The original purpose of astrology, on the other hand, was to inform the individual of the course of his life on the basis of the positions of the planets and of the zodiacal signs (the 12 astrological constellations) at the moment of his birth or conception. From this science, called genethlialogy (casting nativities, often called birth charts), were developed the fundamental techniques of astrology. The main subdivisions of astrology that developed after genethlialogy are general, catarchic, and interrogatory.

General astrology studies the relationship of the significant celestial moments (e.g., the times of vernal equinoxes, eclipses, or planetary conjunctions) to social groups, nations, or all of humanity. It answers, by astrological means, questions formerly posed in Mesopotamia to the bāru.

Catarchic (pertaining to beginnings or sources) astrology determines whether or not a chosen moment is astrologically conducive to the success of a course of action begun in it. Basically in conflict with a rigorous interpretation of genethlialogy, it allows the individual (or corporate body) to act at astrologically favorable times and, thereby to escape any failures predictable from an individual’s birth or group’s moment of origin.

Interrogatory astrology provides answers to a client’s queries based on the situation of the heavens at the moment of his posing the questions. This astrological consulting service is even more remote from determinism than is catarchic astrology; it is thereby closer to divination by omens and insists upon the ritual purification and preparation of the astrologer.

Other forms of astrology, such as iatromathematics (application of astrology to medicine) and military astrology, are variants on one or another of the above.

Astral omens in the ancient Middle East

The astral omens employed in Mesopotamian divination were later commingled with what came to be known as astrology in the strict sense of the term and constituted within astrology a branch described as natural astrology. Though lunar eclipses apparently were regarded as ominous at a somewhat earlier period, the period of the 1st dynasty of Babylon (18th to 16th centuries bce) was the time when the cuneiform text Enūma Anu Enlil, devoted to celestial omina, was initiated. The final collection and codification of this series, however, was not accomplished before the beginning of the 1st millennium bce. But the tablets that have survived—mainly from the Assyrian library of King Ashurbanipal (7th century bce)—indicate that a standard version never existed. Each copy had its own characteristic contents and organization designed to facilitate its owner’s consultation of the omens.

The common categories into which the omens of Enūma Anu Enlil were considered to fall were four, named after the chief gods involved in the ominous communication: Sin, Shamash, Adad, and Ishtar. Sin (the Moon) contains omens involving such lunar phenomena as first crescents, eclipses, halos, and conjunctions with various fixed stars; Shamash (the Sun) deals with omens involving such solar phenomena as eclipses, simultaneous observations of two suns, and perihelia (additional suns); Adad (the weather god) is concerned with omens involving meteorological phenomena, such as thunder, lightning, and cloud formations, as well as earthquakes; and Ishtar (Venus) contains omens involving planetary phenomena such as first and last visibilities, stations (the points at which the planets appear to stand still), acronychal risings (rising of the planet in the east when the Sun sets in the west), and conjunctions with the fixed stars.

Though these omens are often cited in the reports of a network of observers established throughout the Assyrian empire in the 7th century bce, they seem to have lost their popularity late in the period of the Persian domination of Mesopotamia (ending in the 4th century bce). During the later period new efforts were made, in a large number of works called Diaries, to find the correct correlations between celestial phenomena and terrestrial events. Before this development, however, portions of the older omen series were transmitted to Egypt, Greece, and India as a direct result of the Achaemenian dynasty (559 to 330 bce) which dominated Persia and extended as far west as Macedonia and to the Punjab in the east.

Astral omens in Egypt, Greece, India, and China

The evidence for a transmission of lunar omens to Egypt in the Achaemenian period lies primarily in a demotic papyrus based on an original of about 500 bce. A more extensive use of Mesopotamian celestial omens is attested by the fragments of a book written in Greek in the 2nd century bce and claimed as a work addressed to a King Nechepso by the priest Petosiris. From this source, among others, the contents of Enūma Anu Enlil were included in the second book of the Apotelesmatika, or “Work on Astrology” (commonly called the Tetrabiblos, or “Four Books”), by Ptolemy, a Greek astronomer of the 2nd century ce; the first book of an astrological compendium, by Hephaestion of Thebes, a Greco-Egyptian astrologer of the 5th century ce; and the On Signs of John Lydus, a Byzantine bureaucrat of the 6th century. Yet another channel of transmission to the Greeks was through the Magusaeans of Asia Minor, a group of Persian settlers influenced by Babylonian ideas. Their teachings are preserved in several classical works on natural history, primarily that of Pliny the Elder (c. 23–79 ce), and the Geoponica (a late collection of agricultural lore).

In various Middle Eastern languages there also exist many texts dealing with celestial omens, though it is unclear the varying degrees to which they are directly descended from a Mesopotamian tradition or are derived from Greek or Indian intermediaries. Of these texts the most important are those ascribed to Hermes Trismegistos by the Harranians and now preserved in Arabic, the Book of the Zodiac of the Mandaeans (a Gnostic sect still existing in Iraq and southwest Iran), the Apocalypse attributed to the biblical prophet Daniel (extant in Greek, Syriac, and Arabic versions), and The Book of the Bee in Syriac.

The transmission of Mesopotamian omen literature to India, including the material in Enūma Anu Enlil, apparently took place in the 5th century bce during the Achaemenid occupation of the Indus valley. The first traces are found in Buddhist texts of this period, and Buddhist missionaries were instrumental in carrying this material to Central Asia, China, Tibet, Japan, and Southeast Asia. But the most important of the works of this Indian tradition and the oldest extant one in Sanskrit is the earliest version of the Gargasamhita (“Compositions of Garga”) of about the 1st century ce. The original Mesopotamian material was modified so as to fit into the Indian conception of society, including the system of the four varnas and the duty of the upper varnas to perform the samskaras (sanctifying ceremonies).

There are numerous later compilations of omens in Sanskrit—of which the most notable are the Brhatsamhita, or “Great Composition,” of Varahamihira (c. 550), the Jain Bhadrabahu-samhita, or “Composition of Bhadrabahu” (c. 10th century), and the Parishishtas (“Supplements”) of the Atharva Veda (perhaps 10th or 11th century)—though these add little to the tradition. But in the works of the 13th century and later, entitled Tājika, there is a massive infusion of the Arabic adaptations of the originally Mesopotamian celestial omens as transmitted through Persian translations. In Tājika astrology the omens are closely connected with popular concerns as opposed to in the earlier Sanskrit texts where the focus of astrology had been primarily in the fields of military and catarchic (choosing an opportune moment) astrology.

Astrology in China

Although some earlier scholars suggested there was Mesopotamian influence on Chinese astrology, 21st century research suggests that the Chinese astrological system developed independently. The Chinese zodiac possibly can be traced to the Warring States period (475–221 bce), other sources place its beginning in the Qin dynasty (221–207 bce), and others during the Han dynasty (206 bce–220 ce). By the latter half of the Han dynasty the system was firmly established as part of Chinese cultural life.

The Chinese zodiac system is an annual classification system following the Chinese lunar calendar yingyang li (literally, “heaven-earth”) in which each year in a 12-year cycle is assigned an animal and each animal is associated with a personality that typifies the year and those born during that year. The cycle changes to a new animal each year at the Chinese New Year, which falls between January 21 and February 20 on the Gregorian calendar, and the order of animals restarts after going through the cycle of 12 animals. Unlike the Western zodiac system, which is based on months named for constellations, the Chinese zodiac changes its animal sign with each year. Ancient Chinese cosmology also developed the concept of wuxing, the five basic elements of earth, wood, metal, fire, and water. These elements are thought to underlie the universe and their cycles explain change in the cosmos. This cycle of elements intersects with the cycle of 12 zodiac animal signs, thus yielding specific combinations of element and animal and allowing for further predictive specificity for astrological calculations. Countries in east and southeast Asia neighboring or heavily influenced by China have adopted the Chinese zodiac, often giving it their own unique recastings.