It is clear from many passages in the Conciliator that Peter believes that much of a man’s life and character can be inferred from his horoscope. The geniture of a prince may involve the slaughter of vast multitudes in war, although their own horoscopes may not have definitely indicated this fate for them but only a certain inclination in that direction.[2811] Peter devotes considerable space and pains to the process of generation and the problem of measuring the time of nativity. He gives physiological explanations why twins, even before birth, are not under the same astrological influence and approvingly quotes the lines of Lucan:[2812]
Stant gemini fratres fecundae gloria matris
Quos eadem variis genuerunt viscera fatis.
Revolution of the eighth sphere.
In connection with the subdivision of judicial astrology known as revolutions Peter was especially interested in the motion of the eighth sphere of the fixed stars, concerning which we have seen he wrote a distinct treatise[2813] and of which he treats in both the Lucidator[2814] and Conciliator.[2815] Ptolemy had reckoned that the sphere of the fixed stars moved one degree in a hundred years and that consequently the eighth sphere made a complete revolution every 36,000 years. Albategni’s estimate was 23,760 years for a complete revolution or a motion of one degree in the course of sixty-six years. Peter’s own calculation was that one degree was accomplished in seventy years. He regarded this as a matter of great importance because of the vast changes which he believed the revolution of the eighth sphere brought about. Its influence could even change dry land into sea, as the story of the lost island of Atlantis showed. Peter mentions the doctrine of the magnus annus, held by “certain Stoics and Pythagoreans” that history would repeat itself as soon as the eighth sphere had accomplished a complete revolution. His own favorite theory, set forth three times in the aforesaid three works, was that when the heads of the equinoctial and tropical signs of the mobile zodiac come directly under the heads of the same signs of the immobile zodiac in the heaven of the fixed stars, then virtue from the First Cause passes in a more perfect manner through the mediate causes or heavens and men live longer and are stronger. For some five hundred years before and after the period of exact coincidence a golden age occurs, men of genius appear in large numbers, and the world tends to unite under one government. Such a period in Peter’s opinion was that of classical antiquity, when there were great rulers like Darius, Alexander, and Julius Caesar; great minds like Hippocrates, Plato, Aristotle, Stoics and Peripatetics, Euclid, Abrachys, Ptolemy, Galen, Cicero, and Vergil; and when both the Roman law and the Christian religion were promulgated. But then gradually, as the discrepancy between the mobile and immobile signs increases, all is changed to the contrary, human nature deteriorates, the span of life is shortened, monarchy is corrupted, faith and law are made light of, the people are oppressed, and true sages are rare indeed.
Conjunctions.
In a number of places in the Conciliator Peter discusses the subject of the effects of conjunctions of the planets. He states[2816] that very rarely at long intervals of time, when a greatest conjunction of Saturn and Jupiter occurs in the beginning of the sign of the ram, a well-balanced type of constitution[2817] is produced, but never more than a single specimen at one time. Such a man becomes “a prophet, introducing a new law or religion, and teaching sages and men.” Such a man, according to Isaac Amaraan, Avicenna, and Algazetes, is midway between angels and sages, and some say that Moses and Christ were such men. Peter also hints at a coincidence between the length of time that astrology teaches that such a perfectly proportioned physical constitution will last and the duration of Christ’s life. Champier included this passage in his list of Peter’s errors. Champier further attacked the astrological doctrine of great conjunctions and censured Peter for connecting Noah’s flood and the advent of Mohammed with them. In another passage[2818] concerning this same conjunction of Saturn and Jupiter in the first degree of Aries[2819] Peter asserted that it not only altered the strength of human nature and affected the length of life but produced new kingdoms and religions, as in the case of the respective advents of Moses, Nebuchadnezzar, Alexander the Great, Christ, and Mohammed.
The astrological interpretation of history.
This astrological interpretation of history Peter carries out in further detail. As he had divided man’s life into seven ages, so he distributed periods of history among the seven planets. Each presides in turn over human affairs for a period of 354 years and four lunar months, a term analogous to the number of days in the lunar year. When Mars governed the world, the flood occurred because of a greatest conjunction of the planets in the sign Pisces. Under the Moon’s supremacy happened the dispersion of tongues, overthrow of Sodom and Gomorrah, and escape of the children of Israel from Egypt. Peter also alludes to the less significant minor conjunctions which happen every twenty years, to the moderate ones which take place every 240 or 260 years, and to the effects following eclipses. A solar eclipse seventy years ago, he says, was followed by sterility of the soil, movements of phantasms and of good demons and bad demons, intercourse of incubi and succubi, a weakening of human nature and increase of avarice and cupidity.
Chronology.