Astrology has been practiced in one form or another for the past 27,000 years. As far back as 25,000 B.C., the ancients kept track of time by observing the phases of the Moon. But it was during the fourth millennium B.C. that it came to be looked upon as a science with a spiritual foundation which is quite different from the astrology of today. Its spiritual roots can still be found within almost every religion still practiced in the world. For example, the allegories of the Jewish Old Testament, as well as the mythological stories of ancient Greece and Rome, have astrological foundation. In the ancient world man measured his year according to the equinoxes and solstices. And worship of the central celestial sphere -- the Sun -- became one of the earliest forms of religious expression. The grand stone structures of the old world, stretching from Stonehenge in England to the pyramids of Egypt; the towers of Chaldea and the ziggurats of Babylon were all used as temples and observatories to the Sun God and his heavens. From the times of the pagans, the celestial spheres were considered to be sacred, divine entities with power and will that could influence all life on Earth. This belief, in one form or another could be found with the Chaldeans, Chinese, Egyptians, Hindus, and Phoenicians. It was during the first millennium that astrology became the most favored of means of divination by the royalty of nations who used it to protect and guide their domains. In fact, astrological divination was not limited to the Old World, but evidence also points to its use in the New World among the Mayans who calculated their calendars according to their celestial studies and beliefs. sou By the fifth century B.C., astrology had extended to Greece where it had great influence on the most luminous of its citizens like, Aristotle, Democritus and Plato. Advanced understanding of the heavens by Greek astronomer/astrologers gave new structure to the system. It was the Greeks who first divided the celestial zodiac into twelve separate parts. They took note of how the Sun traveled through the zodiacal belt; and believed it added vitality and influences as it illuminated each of the twelve divided sections -- or signs. They created a horoscope chart with ten houses -- influenced no doubt by the Jewish belief in the sanctity of the number ten. In addition, the greatest mathematical mind in Greece, Pythagoras, also believed that the number ten was the most perfect of numbers. source : internet The astrology as we know it today came into use sometime in 323 B.C., shortly after the death of Alexander the Great in Egypt. In Alexandria, the major international city at that time, the astrologer Ptolemy added and changed the ten house system into the system we now know with twelve signs in the zodiac and twelve divisions in the personal horoscope. In the years that followed, the influences of Babylonian and Egyptian astronomy and physics also influenced the system of astrology. It remained in high esteem among both the educated and the illiterate until Christianity took hold -- after which, it fell out of favor. By the age where Nostradamus was considered the greatest physician and seer (who used astrological divination for his predictions), astrology was only something done behind closed doors. It had become a secret practice in the Christian world. This did not change measurably until the nineteenth century.