Originally the Greek word horoskopos denoted the point of the ecliptic rising at any given moment, that is, the intersection of the zodiac with the eastern horizon. Because of the great importance of this point in astrological forecasts, the term came to mean an entire prediction. Hence the ordinary sense of the word horoscope.
Astrological Backgrounds. Many peoples have believed that the heavenly bodies exert a preponderant influence over the world and its inhabitants and that man's fate, at least in part, is fixed in advance and can be predicted by carefully observing at the moment of birth or conception the positions of the sun and moon and the planets in relation to each other, to the signs of the zodiac, and to the eastern and western horizons and midheaven, the highest point of the ecliptic. On this foundation the pseudoscience of astrology was erected. It was a highly complicated and technical structure requiring considerable knowledge of mathematics and astronomy in its practitioners, who often differed from one another in the details and even in the fundamental assumptions of their profession.
Astrologers sometimes made predictions applying to cities, states, or entire regions of the earth. For this purpose the regions of the ancient world were apportioned among the signs of the zodiac according to various systems, of which Ptolemy's (Tetrabiblos 2.3) is the most elaborate. For instance, Britain was assigned to Aries. Eclipses, comets, and other phenomena occurring in Aries and observed in Britain would then be interpreted as applying to Britain.
Genethlialogy. The astrologer's highest knowledge was exhibited in genethlialogy, the art of prediction applied
to an individual, based on the positions of the heavenly bodies at the moment of his birth. Each planet was believed to have its own nature and influence, which were nevertheless capable of great variation, just as the gods were variable and capricious.
Houses and Loci. Each planet had its day and night houses, or signs of the zodiac in which it was especially "at home," where its natural influence would be accentuated; its exaltation and depression, particular degrees of the ecliptic where its influence would be maximum or minimum; and its terms, a fixed section in each sign of the zodiac. For example, Mars had its day house in Scorpio and its night house in Aries; its exaltation at 28° in Capricorn and its depression at 28° in Cancer; and a term of a certain number of degrees, arranged on any of three systems, in each sign. In addition, each planet might affect various features of a man's life, depending on its location in one of the 12 loc. The significance of the loci was as follows: I, life, body, spirit or breath; II, livelihood, property, partnership, intercourse with women, business, profit from inheritance; III, brothers, living abroad, royalty, wealth, friends, relatives, slaves; IV, parents, spirits, life in the temple, repute, children; V, children, good fortune, friendship, accomplishments, marriage; VI, slaves, bad fortune, illness, enmity, infirmity; VII, marriage; VIII, death, trial, penalty, loss, weakness; IX, travel, friendship, benefit from kings, revelations, manifestations of gods, soothsaying; X, careers and honors, accomplishment, reputation, children, wife; XI, "good daemon," friends, hopes, gifts, children, freed persons, accomplishment; and XII, "bad daemon," enmity, foreign country, slaves, illness, dangers, court trials, infirmity, death.
Aspects of the Planets. More important than the loci were the aspects of the planets, the angles at which they "looked at" one another and the earth, depending on their relative positions in the signs of the zodiac. Astrologers recognized conjunction of planets in the same sign and four aspects as especially important. (1) Opposition: this occurs when two planets are in opposite signs, as Aries and Libra. (2) Trine aspect: the 12 signs can be connected by threes to form equilateral triangles, such as Aries, Leo, and Sagittarius, so that planets in any two of such a set are in trine aspect. (3) Quartile aspect: similarly, the signs can be connected by fours to form squares, e.g., Aries, Cancer, Libra, Capricorn; planets in Aries and Cancer or in Aries and Capricorn are in quartile aspect.(4) Sextile Aspect: the 12 signs can be connected to form two different equilateral hexagons; thus, a planet in Aries is in sextile aspect to one in Gemini or Aquarius. Opposition was regularly, and quartile aspect generally, considered ill-omened; trine and sextile aspects, favorable.
Elaboration of Horoscopes and Their Wide Use. Horoscopes of a simple type have been found in great numbers in the "library" of the Assyrian king Assurbanipal (7th century b. c.) at Nineveh (now in the British Museum). Great elaboration became possible only when Babylonian doctrines were combined with Hellenistic Greek astronomy in Egypt, culminating in the astronomical works and extant handbook of astrology, the Tetrabiblos, of Claudius Ptolemaeus (2d century a.d.). Representative Roman works are the Astronomica of Manilius (fl. early 1st century a.d.) and the handbook by Vettius Valens (2d century a.d.). Horoscopes were widely used in the Green-Roman period by all classes, from the Roman emperor to the humblest slave. The curious hold that astrology had on men is well illustrated by the fact that Constantine, after his victory over Licinius, removed the sun-god Helios from his coins, but had an astrologer cast the horoscope of his new capital, Constantinople.
The Church Fathers opposed astrology, but it revived during the Byzantine renaissance of the 9th century, when Greek astrology was rediscovered along with astronomy. From then on astrology flourished and horoscopes were east although the Church officially was opposed. In the later Middle Ages the Universities of Padua, Bologna, and Paris (among others) provided expert instruction in casting horoscopes. Most of the leading astronomers of the age of the Renaissance and the Reformation, among them Tycho Brahe, Copernicus, Galileo, and Kepler, practiced astrology; and all the rulers of the time, including several popes, employed official astrologers at their courts. The art of casting horoscopes still flourishes, and this form of astrology continues to have a surprising number of adherents at all intellectual levels.
See Also: astral religion; astrology; magic.
Bibliography: Ptolemy, Tetrabiblos, ed. f. e. robbins, with Eng. tr. (Loeb Classical Library 1940). bouchÉ-leclercq, L'Astrologie grecque (Paris 1899), still the best account of Greco-Roman techniques. f. w. boll, Sternglaube und Sterndeutung, 4th ed. w. gundel (Leipzig 1931), brief on technique but excellent on history. o. neugebauer and h. b. van hoesen, Greek Horoscopes (Philadelphia 1959), 1,099 Greek horoscopes with astronomical commentary, glossary of terms, and bibliography. j. h. crehan, "Astrology and Theology", h. f. davis. et al., A Catholic Dictionary of Theology (London 1962–) 1:179–182.
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