Classtrology

Ronald Reagan, the Emperor Caligula, Claudius, Ptolemy, St Augustine, Queen Elizabeth I and Heinrich Himmler all share an interest in astrology.
Before describing how astrology and its relationship with society have developed throughout the centuries, it is important to clarify the common confusion between astronomy and astrology: Astronomy is concerned with the observation of the movement of heavenly bodies. It is a very complicated study that is considered scientific by all other scientific disciplines. Astrology, on the other hand, is the study of the effects that the movements of these heavenly bodies have on human lives. Whether astrology is scientific or not, is a question riddled with argument and counter argument.
From the dawn of humanity, people have looked to the heavens and the planets for answers to their questions. Thousands of years ago astrology was, generally speaking, reserved only for members of royalty. This had both advantages and disadvantages. One of the key advantages was that an astrologer could look forward to a nice, comfortable, civil service job in the palace. One of the worst major difficulties were the consequences if an astrologer made the royal person angry by predicting a bad future. The astrologers could lose their head over the matter.
The roots of Western astrology date back to ancient Mesopotamia. From there, astrology entered ancient Greece. Astrology's entrance into Greece is situated in the period of the great Greek philosophers (Socrates, Plato, Aristotle) and the rise of the Greek state and culture.

In the process of "hellenizing" the world - Egypt became the cultural center of ancient Greek thought and philosophy. It was during this period of time that the study, development, and acceptance of astrology flourished among the prominent thinkers of the day... and it was during this period of time, when horoscopic, zodiacal, individualized astrology - much as we recognize it today - first came into existence. In the Hellenistic Greek atmosphere, astrology was no longer reserved for royalty.
Astrology in the Western world became rather quiet during the Middle Ages. During this time, astrology continued to flourish and evolve in other parts of the world. At times Christian church leaders condemned astrology and astrologers, while at other times church leaders needed the guidance of astrologers. Some church officials during this very large span of time, such as French Cardinal Pierre d'Ailly(1350-1420), were practicing astrologers.
After the dark centuries of the Middle Ages, astrology regained its success. During the European Renaissance, the majority of Western astrologers were practicing Christians. The European Renaissance was then followed by the bright rationalistic light of the Age of Enlightenment and Scientific Revolution of the 17th century AD, with the scientific world finally determining, once and for all, that the Earth was not the center of the universe.
What we today take for granted, knowing the Earth to be a small planet in the greater whole of the universe, was - for the peoples of that time and age - a huge shock.
As a result of this ideological earthquake, the physical science of astronomy and the metaphysical art of astrology became separate, often contrary disciplines. While astronomy grew under the watchful eye and blessing of the new Age of Enlightenment - mystically minded astrology was cursed. Once again, Western astrology began disappearing into the mist, shadows, and darkness. At the same time, it would be a mistake to say that the practice of astrology totally died out as a result of the Age of Enlightenment.
Then, around 150-180 years ago, astrology in Western society slowly began rising up once more into public favor, imagination, and consciousness. At the beginning of the 20th century, there was a final grand revival because of the controversial astrologers, Sepharial and Alan Leo, who became the founding fathers of the Astrological Lodge of the Theosophical Society in Great Britain. Since Sepharial and Leo's time, Western culture's fascination with astrology has continued on with us and grown and evolved through the years.
It was during the final 20th century popular revival of Western astrology that birthsign Astrology, ideas on karma and reincarnation, and the reading of daily horoscopes became popular among the majority of mankind. Today, almost every person in Western society knows his/her birthsign and many read their daily horoscope as a source of entertainment and amusement.

Sources:
http://www.astrologie.ws/
http://www.astrology.com/parkersindex.html
http://www.astroquest.com/historyn.htm
Helmers, T. (1997), De Tarot en andere orakels, Utrecht.