HOROSCOPE (ὨΡΑΚΆΠΗΣ). - The term h. designates in astrology the precise moment (ὥρα) at which one observes (σκοπεῖν) the position of the stars that rise on the horizon at the instant of an individual's birth. The exact determination of that moment is necessary in order to establish the individual's future; and also in order to interrogate the stars during the course of his life, though always subject to the position that these had at the moment of his birth.
As can be seen, the h. is firmly connected with divinatory astrology, which rests on the following principles: a) the stars have a preponderant action in the equilibrium of the universe, which is influenced by the characteristic qualities of each of them; b) this influence is determined by the position, at a given moment, of the stars in the sky and can be positive or negative, that is, favorable or adverse. Each of the 7 planets (Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn) has its own house (οἶκος, mansio) in one of the 12 signs of the zodiac, where it draws its greatest energy (Firmicus) and from which it exercises its own influence. Moreover, once these planets had been identified with determinate ages of life (e.g., Moon = earliest infancy, Mercury = youth, etc., down to Saturn = decrepitude [Ptolemy, IV, 9]) and certain good or bad characteristics had been attributed to the zodiacal signs, it was held that there existed an analogy and a very strong bond between the child who is born and the star that at that moment rises in the sky; at the horizon, therefore, where the stars possess all the vigor of youth, astrology placed the h., that is, the precise point at which the moment of birth is linked with destiny.
The h., like astrology, originated in Babylonia, whence it spread; it was much in use among the rulers of Asia Minor, some of whom carved their theme of geniture in temples, on tombs, on coins, etc. In Greece (where the term also denotes the instrument for determining the position of the stars that would have been invented by Anaximander: Diogenes Laertius, II, 1) the o. was in use only from the Alexandrian era (cf. Hesychius and Suidas, s. v.; cf. also Clement of Alexandria, Strom., VI, p. 757). In Rome it was treated particularly in the Augustan age by Manilius, and in the 4th century by Firmicus Maternus, who wrote a treatise on astrology: Matheseos libri VIII.
Bibliography
Cesare D'Onofrio