By late empire days, everyone in Rome gravely consulted the stars; but the old order was completely reversed. So fearful were the Romans of uttering an evil word, that no astrologer was allowed to mention the fortune of the emperor, or even to look in the stars for prophecy about his imperial majesty. The emperors were forced to consult the astrologers on the sly.
The Christian emperors, but none before them, forbade all astrology; nevertheless the Christian notion of the individualsoul, made in God's image, gave a second impetus to the powers of astrology.
This idea came from a theory which was deep-rooted in the earliest human psychology of all nations, though it did not find its complete expression until the Middle Ages, when, with Christian background, but heretical leanings, the necromancers of Persia and Arabia elevated it into a complete and consistent philosophy. God had created man in his own image, and in his own image he had likewise created the universe. Things which are equal to the same thing are equal to one another. Q. E. D.
It followed (if the theory be taken literally) that the universe and human life follow the same pattern; that the macrocosm--the great structural order of the universe--was identical with the microcosm--the small arrangement of the individual life.
Granted the premise, the whole theory was perfectly logical; and even the premise cannot wholly be cast aside, for the astounding research of physics in the twentieth century has done more than any medieval dogmas to prove microcosms and macrocosms, since the smallest particles of matter are said to resemble the largest, and the components of atoms go whirling around with much the same laws and distribution as the planetary systems.
Still, with the premise, as it was accepted in the Middle Ages, there were a number of faults. In the first place, the human body rather than the atom was said to resemble the universe; and in the second place, everything was taken much too literally. No modern scientist would dare to carry his analogy into minute detail, or say that the fourth electron from the center must shine bright red because Mars is such a color; or that the third electron must be inhabited by human beings who study the structure of the whole. But that, in effect, was just what the medievalists did with their astrology.
Each part of the human body was thought to have its counterpart in the stars; there were twelve divisions from head to foot each governed by a sign of the zodiac. Some of the loveliest and most meticulous of early illuminations show man as the center of his universe, surrounded by the zodiac with connecting lines, from Aries to the head, from Taurus to the neck, and so forth. The divine world was divided into two great divisions--man, and everything else; but those two were (if our eyes had light enough to see) only a single reflection of godliness.
The planets, whose discovery had been welcomed by the Babylonians for this very purpose, had their due influences. Their irregular movements helped to account for the vagaries of human life. Usually the characteristic of the God who bore the same name as the planet gave the interpretation. Thus Mercury signified elusiveness, and probably he gave his name to the whimsical Mercutio of Romeo and Juliet; Venus, most beautiful of planets and goddesses, reigned over the field of secular love. Ruddy Mars was symbolical of War, and Saturn, which appears so dull to the naked eye, was lord of Melancholy. The names, at least as adjectives, survive. A man is said to be mercurial or martial or jovial or saturnine depending upon his disposition; and his disposition according to the astrologers, depended upon the planets.
To divine the effects of the heavenly bodies and their influences upon mortal affairs, some particular time had to be selected when the stars were read. To forecast the life of a child, the moment of birth was usually chosen, the time when he uttered his first cry. Then the stars were carefully studied, and, if their subsequent movements were known, the progress of the child could likewise be traced. "Monsieur Parolles," said Helena, in All's Well That Ends Well, "you were born under a charitable star."
PAROLLES: Under Mars, I.
HELENA: I especially think, under Mars.
PAROLLES: Why under Mars?
HELENA: The wars have so kept you under that you must
needs be born under Mars.
PAROLLES: When he was predominant.
HELENA: When he was retrograde, I think, rather.
PAROLLES: Why think you so?
HELENA: You go so much backward when you fight.
Incidentally a planet when retrograde was not supposed to have any influence, but Shakespeare was never a very good astronomer, much poorer than Chaucer, and far, far behind Francis Bacon, who therefore could hardly have written Shakespeare's works with such careful study of many things, and such poor astronomy.