The zodiac originated as a device for measuring time: no one knows how it first became involved in the classification of personalities or attempts to predict the future, although the first known personal horoscope was drawn up in 410 BC, and the zodiac certainly existed by 500 BC. There is evidence that the "modern" zodiac was in place long before the birth of Christ. When pluto wrote about astrology in 365 BC the signs were still ruled by gods and goddesses and were linked to myths from Babylon, Egypt and Assyria, and much modern astrological interpretation relates very powerfully to myth, since these concepts form a background to human behavior and motivation.
Just a little introductory to get things started. Feel free to ask and discuss anything thats on your mind that has to do with the metaphysical!