ASTROLOGY, the ancient art or science of divining the fate and future of human beings from indications given by the positions of the stars and other heavenly bodies. The study of astrology and the belief in it, as part of astronomy, is found in a developed form among the ancient Babylonians, and, directly or indirectly through the Babylonians, it spread to Greece about the middle of the 4th century B.C., and reached Rome before the opening of the Christian era. In India and China astronomy and astrology largely reflect Greek theories and speculations ; and similarly, with the introduction of Greek culture into Egypt, both astronomy and astrology were actively cultivated in the region of the Nile during the Hellenistic and Roman periods. Astrology was further developed by the Arabs from the 7th to the 13th century, and in the Europe of the 54th and 15th centuries astrologers were dominating influences at court.
If moon and sun, whose regular movements produced the con ception of the reign of law and order in the universe as against the more popular notion of chance and caprice, were divine pow ers, the same held good of the planets, of which five were recog nized—Jupiter, Venus, Saturn, Mercury and Mars—to name them in the order in which they appear in the older cuneiform literature; in later texts, Mercury and Saturn change places. These five planets were identified with the great gods of the pantheon as follows:—Jupiter with Marduk (q.v.), Venus with the goddess Ishtar (q.v.), Saturn with the god Ninib, Mercury with Nebo (q.v.), and Mars with Nergal (q.v.). The movements of the sun, moon and five planets were regarded as representing the activity of the five gods in question, together with the moon god Sin (q.v.) and the sun-god Shamash (q.v.), in preparing the occurrences on the earth. The priests of Babylonia accordingly applied themselves to the task of perfecting a system of interpre tation of the phenomena to be observed in the heavens, and it was natural that the system was extended from the moon, sun and five planets to the more prominent and recognizable fixed stars. That system involved not merely the movements of the moon, sun and planets, but the observation of their relative posi tion to one another and to all kinds of peculiarities noted at any point in the course of their movements. To all these phenomena some significance was attached, and this significance was naturally intensified in the case of such a striking phenomenon as an eclipse of the moon. By the same method of careful observation of the sun and planets, and later of some of the constellations and of many of the fixed stars, the body of observations and the inter pretations assigned to the nearly endless variations in the phe nomena thus observed grew to enormous proportions. The inter pretations themselves were based chiefly (I ) on the recollection or on written records of what in the past had taken place when the phenomenon or phenomena in question had been observed, and (2) on association of ideas, involving sometimes merely a play upon words in connection with the phenomenon or phe nomena observed. Thus if on a certain occasion the rise of the new moon in a cloudy sky was followed by victory over an enemy or by abundant rain, the sign in question was thus proved to be a favourable one and its recurrence would be regarded as a good omen. On the other hand the appearance of the new moon earlier than was expected was regarded as an unfavourable omen prog nosticating in one case defeat, in another death among cattle, not necessarily because these events actually took place after such a phenomenon, but on a general principle resting upon association of ideas, whereby anything premature would suggest an unfa vourable occurrence.
Astrology in this its earliest stage is marked by two char acteristic limitations. In the first place, the movements and posi tion of the heavenly bodies point to such occurrences as are of public import and affect the general welfare; individual interests are not in any way involved. In Babylonia and Assyria the cult centred almost exclusively in the public welfare and the person of the king, because upon his well-being and favour with the gods the fortunes of the country were dependent in accordance with the ancient conception of kingship (see J. G. Frazer, The Early History of Kingship). In the second place, the astronom ical knowledge presupposed and accompanying early Babylonian astrology is essentially of an empirical character. In a general way the reign of law and order in the movements of the heavenly bodies was recognized, and indeed must have led to the rise of a methodical divination. We have, probably, as early as the days of Khammurabi, the combinations of prominent groups of stars with outlines of pictures fantastically put together. The theory of the ecliptic as representing the course of the sun through the year, divided among twelve constellations with a measurement of 3o° to each division, is also of Babylonian origin, perfected after the fall of the Babylonian empire in 539 B.C. The golden age of Babylonian astronomy belongs to the Seleucid period, i.e., after the advent of the Greeks in the Euphrates Valley. The beginnings at least of the calculation of sun and moon eclipses belong to the earlier period. Recent investigations have shown that the precession of the equinoxes was known to Babylonian astronomers.
Chiefly under Greek influences, the scope of astrology was enlarged until it was brought into connection with practically all of the known sciences: botany, chemistry, zoology, mineralogy, anatomy and medicine. Colours, metals, stones, plants, drugs and animal life of all kinds were associated with the planets and placed under their tutelage. In the system that passes under the name of Ptolemy, Saturn is associated with grey, Jupiter with white, Mars with red, Venus with yellow, while Mercury, occu pying a peculiar place in Greek as it did in Babylonian astrology (where it was at one time designated as the planet par excellence), was supposed to vary its colour according to changing circum stances. The sun was associated with gold, the moon with silver, Jupiter with electrum, Saturn with lead, Venus with copper, and so on, while the continued influence of astrological motives is to be seen in the association of quicksilver, upon its discovery at a comparatively late period, with Mercury, because of its change able character as a solid and a liquid. In the same way, stones were connected with both the planets and the months; plants, by diverse association of ideas, were connected with the planets, and animals likewise were placed under the guidance and pro tection of one or other of the heavenly bodies. By this curious process of combination the entire realm of the natural sciences was translated into the language of astrology with the single avowed purpose of seeing in all phenomena signs indicative of what the future had in store. The fate of the individual, as that feature of the future which had a supreme interest, led to the association of the planets with parts of the body. Here, too, we find various systems devised, in part representing the views of different schools, in part reflecting the advancing conceptions regarding the functions of the organs in man and animals. From the planets the same association of ideas was applied to the con stellations of the zodiac, which in later phases of astrology are placed on a par with the planets themselves, so far as their im portance for the individual horoscope is concerned. The fate of the individual in this combination of planets with the zodiac was made dependent, not merely upon the planet which happened to be rising at the time of birth or of conception, but also upon its local relationship to a special sign or to certain signs of the zodiac. The zodiac was regarded as the prototype of the human body, the different parts of which all had their corresponding sections in the zodiac itself.. The late Egyptian astrologers set up a correspondence between the 36 decani recognized by them and the human body, which is thus divided into 36 parts; to each part a god was assigned as a controlling force. Many diseases and disturbances of the ordinary functions of the organs were attributed to the influence of planets or explained as due to con ditions observed in a constellation or in the position of a star; while, on the other hand, the influence of planetary lore appears in the assignment of the days of the week to the planets, begin ning with Sunday, assigned to the sun, and ending with Saturday, the day of Saturn. In later periods, Saturn's day was associated with the Jewish Sabbath; Sunday with the Lord's Day; Tues day with Tiw, the god of war, corresponding to Mars of the Romans and to the Nergal of the Babylonians. Wednesday was assigned to the planet Mercury, the equivalent of the Germanic god Woden; Thursday to Jupiter, the equivalent of Thor; and Friday to Friga, the goddess of love, who is represented by Venus among the Romans and among the Babylonians by Ishtar. Astro logical considerations regulated in ancient Babylonia the distinc tion of lucky and unlucky days, which passing down to the Greeks and Romans (dies fasti and ne f asti) found expression in Hesiod's Works and Days.
Judicial astrology, as a form of divination, is a concomitant of natural astrology, in its purer astronomical aspect, but mingled with what is now considered an unscientific and superstitious view of world-forces. Francis Bacon abuses the astrologers of his day no less than the alchemists because he has visions of a reformed astrology and a reformed alchemy. Sir Thomas Browne, too, while he denies the capacity of the astrologers of his day, does not dispute the reality of astrological science. But Aristarchus of Samos, Martianus Capella (the precursor of Copernicus), Cicero, Favorinus, Sextus Empiricus, Juvenal, and in a later age Savonarola and Pico della Mirandola, and La Fontaine, a contemporary of the neutral La Bruyere, were all pronounced opponents of astrology. In England Swift may fairly claim the credit of having given the death-blow to astrology by his famous Prediction for the Year r7o8, by Isaac Bickerstaff, Esq. Many passages in the older English poets are unintelligible without some knowledge of astrology. Chaucer wrote a treatise on the astro labe; Milton constantly refers to planetary influences; in Shake speare's King Lear, Gloucester and Edmund represent respec tively the old and the new faith. In modern languages words with astrological associations are still in use, such as lunatic, saturnine, malheureux and ill-starred.