his younger days had busied himself ^vith astrologj', protested vigorously, but without success, against it in his work " De Divinatione". The Emperor Augustus, on the other hand, believed in astrology and protected it. The first Roman work on astrology was dedicated to him; it was the "Astronomica «Titten about 45 B. c. by JIarcus Manilius, who was probably a Chaldean by birth. In five books this poem gives an outline of the astrologj^ of the zodiac and constellations. The fifth book is devoted to the spluera harbarica. It is a curious fact that the poem does not take up the astrology of the planets. In spite of repeated attempts to suppress it, as in the reigns of Claudius and Vespasian, astrology main- tained itself in the Roman Empire as one of the lead- ing forms of culture. The lower the Romans sank in religion and morals the more astrology became entwined with all action and belief. Under Tiberius and Nero the two astrologers named Thrasyllus, who were father and son, held high political positions. The most distingui.shed astronomer of antiquity, Claudius Ptolemseus, was also a zealous astrologer. His "Opus Quadripartitum, seu de apotelesmatibus et judiciis astrorum, libri IV" is one of the chief treatises on astrologj- of earlier times and is a detailed account of astrological teachings. This work occu- pied in astrologj- as important a position as that which the same author's MevaX?; Sy^rafis (also called "Almagest"), held in the science of astronomj' before the appearance of the Copernican theory. It is a striking fact that Ptolemy sought, in the second book of the "Opus Quadripartitum", to bring the psychi- cal and bodilj- differences of the various nations into relation with the phj-sical conditions of their native lands, and to make these conditions, in their turn, depend on the positions of the stars. The Roman astrologers wTOte their manuals in imitation of Ptolemy, but with the addition of mystic phantasies and predictions. After the death of Marcus Aurelius, the Chaldeans were alwaj-s important personages at the imperial court. As late as the time of Constan- tine the Great the imperial notary Julius Firmicus Maternus, who later became a Christian, wrote on "Mathematics, or the power and the influence of the stars" eight books which were the chief authority in astrology until the Renais.sance. With the overthrow- of the old Roman Empire and the victorj' of Chris- tianity, astrology lost its importance in the centres of Christian civilization in the West. The last known astrologer of the old world was Johannes Laurentius (sometimes called Lj-dus), of Philadelphia in Lydia, who lived a. d. 490-565.
AsTROLOGV Under Chrlstianity. — From the start the Christian Church strongly opposed the false teachings of astrologj-. The Fathers energetically demanded the expulsion of the Chaldeans who did .so much harm to the State and the citizens by em- ploying a fantastic mysticism to plaj' upon the in- eradicable impulses of the common people, keeping their heathen conceptions alive, and fostering a .soul- perplexing cult which, with its fatalistic tendencies, created difficulties in the di.scemment of right and wrong and weakened the moral foundations of all human conduct. There was no room in the early Christian Church for followers of this pseudo-science. The noted mathematician Aquila Ponticus was ex- pelled from the Christian communion, about the year 120, on account of his astrological heresies. The early Cliristians of Rome, therefore, regarded the astrologers as their bitterest and, unfortunately, their too powerful enemies; and the astrologers probably did their part in stirring up the cruel persecutions of the Christians. As Christianity spread, the a.s- trologers lost their influence and reputation, and gradually sank to the position of mere quacks. The conversion of Constantine the Great put an end to the importance of this .so-called science, which for
five hundred years had ruled the public life of Rome. In 321 Constantine issued an edict threatening all Chaldeans, Magi, and their followers with death. Astrology now disappeared for centuries from the Christian parts of Western Europe. Only the Arabic schools of learning, especially those in Spain after the Moors had conquered the Iberian peninsula, ac- cepted this dubious inheritance from the wisdom of classic times, and among the Arabs it became an in- centive to pure astronomical research. Arabian and Jewish scholars were the representatives of astrology in the Middle Ages, while both Church and State in Christian countries rejected and persecuted this false doctrine and its heathen tendencies. Unfortunately, at the same time the development of astronomy was checked, excepting so far as it was needed to estab- lish certain necessary astronomic principles and to calculate the date of Easter. Yet early Christian legend distinguished between astronomy and as- trology by ascribing the introduction of the former to the good angels and to Abraham, while the latter was ascribed to Cham. In particular, St. Augustine ("De civitate Dei", VIII, xix, and in other places) fought against astrology and sought to prevent its amalgamation with pure natural science. Once more the East prepared a second period of prosperity for astrology. The Jews, very soon after they were driven into Western Europe, busied themselves with astrological questions, being stimulated thereto by the Talmud. Jewish scholars had, moreover, a knowl- edge of the most important works of classic times on astrology and they became the teachers of the Arabs. These latter, after the rapid spread of Mo- hammedanism in Western Asia and North Africa, and their defeat in Western Europe by Charles Mar- tel, began to develop a civilization of their own. The mystical books which appeared in Jewish literature after the time of theTalmud, that is. the books called the " Sefer Zohar " and the "Sefer Yezirah" (Book of Creation), are full of riiles of divination dealing especially with astrological meanings and calculations. The high reputation of the Talmud and the Cabbala among the Jews in the Middle Ages explains their fondness for astrological speculations; but at a verj- early date, it should be noted, they distinguished between astronomy, " the science of reading the stars ' '. and astrology, "the .science of divination".
Caliph Al-Mansur, the builder of Bagdad, was, like his son, the famous Harun-al-Rashid, a promoter of learning. He was the first caliph to call Jewish scholars around him in order to develop the study of the mathematical sciences, especially astronomj-. in his empire. In the year 777 the learned Jew Jacob ben Tarik founded at Bagdad a school for the studj- of astronomy and astrology which soon had a high reputation; amon^ those trained here was Alchindi (Alkendi), a noted astronomer. It was one of Al- chindi's pupils, Abumassar (.\bu Mashar), from Balkh in Chorassan, born about the year 805, whom the Middle Ages regarded as the greatest of Arabian as- trologers. Astrology being regarded by the caliphs as the practical application of astronomy, all the more important Arabic and Jewish astronomers who were attached to that court, or who taught in the Moorish schools were also astrologers. Among the noteworthy Jewish astrologers may be mentioned Sahl ben Bishr al-Israel (about S20); Rabban al-Ta- ban, the well-known cabbalist and Talmudic scholar: Shabbethai Donalo (913-970), who wrote a commen- tary on the astrology of the "Sefer Yezirah" which Western Europe later regarded as a standard work; and, lastly, the Jewish lyric poet and mathematician Abraham ibn Ezrah. Among the noted Arabic as- tronomers were Massah Allah Albategnius, Alpe- tragius, and others. The Arabo-Judaic astrologj- of the Middle Ages pursued the path indicated by Ptolemy, and his teachings were apparently the in>-