There was, however, another popular superstition or belief which, about the time when Mithraism made its appearance in Europe, had spread itself over Western Asia. This was the idea that the positions and changes of the heavenly bodies exercise an influence over the affairs of the world and the lot both of kingdoms and individual men. It probably began in Babylonia, where the inhabitants had from Sumerian times shown themselves great observers of the stars, and had been accustomed to record the omens that they drew from their motions for the guidance of the kings[811]. This kind of divination—or astrology to call it by a familiar name—received a great impulse after Alexander’s Conquest, in the first place from the break up of the Euphratean priestly colleges before referred to, and the driving out of the lesser priests therein to get their own living, and then from the fact that the scientific enquiry and mathematical genius of the Greeks had made the calculation of the positions of the heavenly bodies at any given date and hour a fairly simple matter to be determined without direct observation[812]. It was probably no mere coincidence that the Chaldaei and the Mathematici, as the astrologers called themselves, should have swarmed at Rome under just those emperors in whose reigns Mithraism began to push itself to the front[813]. While we may be sure that these factors, the religion of the Magi, the practice of magic, and the astrological art, all counted in the composition of the worship of Mithras, we yet know but very little of its tenets. No work has come down to us from any devotee of Mithras which will give us the same light on the way his worshippers regarded him that the romance of Apuleius and the encomium of Aelius Aristides have cast on the mental attitude of the devotees of the Alexandrian cult. The extensive books of Eubulus and Pallas on Mithras and the history of his worship, which Porphyry tells us were extant from the reign of Hadrian down to his own time[814], are entirely lost, and our only source of information, except a very few scattered notices in the Fathers and in profane writers like the Emperor Julian and Porphyry himself, are the sculptures and inscriptions which have been found in his ruined chapels. These texts and monuments the scholarly care of M. Cumont has gathered into two large volumes, which will always remain the chief source from which later enquirers must draw their materials[815]. From their study he comes to the conclusion that, in the religion of Mithras, there figured above him the Mazdean gods of good and evil respectively called in the Zend Avesta Ahura Mazda and Angro Mainyus, or in more familiar language, Ormuzd and Ahriman. Behind and above these again, he would place a Supreme Being called Zervan Akerene or Boundless Time, who seems to be without attributes or qualities, and to have acted only as the progenitor of the opposing couple. This is at first sight