The groups of stars which now bear the name ‘Twelve Signs of the Zodiac’ were mapped out for the first time, and the planets Mercury, Venus, Mars, Jupiter and Saturn were known. . . .
Medical astrology posits the association of each sign of the zodiac with parts of the body, and was already mentioned by Marcus Manilius (1st century AD) in his epic poem (8000 verses) Astronomica.
If the event involves the tropical signs of the zodiac, the effects could be related to politics, whereas fixed signs indicate foundations and constructions of buildings, whilst common signs indicate men and kings.
Such connections were taken up by Thomas Mann, who in his novel Joseph and His Brothers attributes characteristics of a sign of the zodiac to each tribe in his rendition of the Blessing of Jacob.
The horoscope is “a diagram of the relative positions of planets and signs of the zodiac at a specific time (as at one’s birth)” and is used by astrologers to try to foretell future events in a person’s life.
It was not until the second century B.C.E., however, that a Greek astronomer divided the zodiac into 12 equal parts of 30 degrees each; these parts came to be called the signs of the zodiac and were named after the related constellations.
Ptolemy explains that the definitions of the zodiac are not his own, but present "the natural characters of the zodiacal signs, as they have been handed down by tradition".
Although the belief and tradition of the zodiac sign has been over thousands of years, the trend of using it in making major decisions did not really happen until the past few decades.
In conjunction with Olympic Expo Beijing 2008, souvenir sheets and a special event sheet were issued composed of the Chinese zodiac sign “Year of the Rat” and the text “Sport for Peace”, with Olympic rings appearing on the tabs of the stamps alternately.
There have been reforms of the solar version of the Hindu calendar which changed the distribution of the days in each month to better match the length of time that the Sun spends in each sidereal zodiacal sign.
These horas, astrologers say, are ruled alternatively by the sun and the moon, with the order of control changing, depending on whether the zodiacal sign is odd or even.