The oldest that is known to us in the West is that invented by Claudius Ptolemy in the second century. It is developed in the _Tetrabiblos_ or Four Books on the Influence of the Stars, translations of which are easily obtained, the best being that by Ashmand. Under the head of Chronocrators, the Seven Ages of Man, so graphically described by the bard in _As You Like It_, are for the first time mentioned and placed under the dominion of the seven planets of the ancient solar system. Ptolemy’s invention consists in ascribing to these ages the number of years they extend, and applying to them certain periods of the planets and luminaries. Thus he makes the Moon to rule the first four years of life, the infant “mewling and puking in the nurse’s arms”; the next ten years are under Mercury, and denote the “schoolboy, with ... shining morning face, creeping like snail unwillingly to school.” The next eight years are under Venus, and represent “the lover, sighing like furnace, with a woeful ballad made to his mistress’ eyebrow.” The next nineteen are under the influence of the Sun, according to Ptolemy. The next fifteen under that of Mars, denoting the “soldier ... bearded like a pard ... sudden and quick in quarrel.” Jupiter rules the next twelve years and represents “the justice ... full of wise saws and modern instances.” Saturn, ruling the next thirty years, figures “the lean and slippered pantaloon.” Here the system of Ptolemy ends, and to this the poet, with that prophetic apprehension of ulterior need, adds a truly Uranian picture of that “second childishness and mere oblivion” which characterizes paralytic dotage. Astrologers have sought to apply this system of Chronocrators to the horoscopes of persons by taking into consideration the aspects held by these planets at the time of birth and judging of the period under consideration accordingly. Thus a person at whose birth Mars is an afflicting planet, as may be seen by its aspects to the Sun, Moon and other significant points of the horoscope, would suffer many troubles and misfortunes during the period from forty-one to fifty-six years of his age. One in whose horoscope Jupiter is a beneficent planet, as judged by its aspects, would similarly have good fortune and experience many benefits during the period of Jupiter from fifty-six to sixty-eight years of age. So in regard to the other Chronocrators. The scheme is set out in the following table— Table of Chronocrators _By Ptolemy._ Moon 4 years. From 1 to 4 inclusive. Mercury 10 ” ” 5 ” 14 ” Venus 8 ” ” 15 ” 22 ” Sun 19 ” ” 23 ” 41 ” Mars 15 ” ” 42 ” 56 ” Jupiter 12 ” ” 57 ” 68 ” Saturn 30 ” ” 69 ” 98 ”