Contrary to its popular but erroneous reputation as a New Age subject, astrology is actually an ancient science that predates both astronomy and psychology. Studied and used throughout the world for thousands of years, astrology is the study of the interactions among the stars and the planets, based on intricate mathematical cycles.
The earliest known astrological records date back to Babylon, 1645 BC, and the earliest horoscope to 410 BC. Astrology's origins can also be traced to several other locations and cultures, including Egypt, which developed sophisticated timekeeping and calendar science; Greece, where Ptolemy authored influential astrological and astronomical texts; and Rome, where many of the most learned men -- including two emperors -- were astrologers who wrote laws and counseled citizens based on the stars.
During the Renaissance, when literacy became more widespread, almanacs began publishing astrological information for public consumption. Several notable figures of the era, including Galileo and Copernicus, were both practicing astrologers and founders of the modern scientific movement. Despite the seemingly easy relationship between astrology and science, however, astrology began to lose popular credibility when myriad predictions about the great conjunction of 1524 failed to "come true."
As the scientific revolution surged and astronomy gained respect, astrology and various other arts fell by the wayside. Many individuals still practiced the art, however, and astrology enjoyed small revivals in England in the 1700s and 1800s. But it wasn't until the birth of Princess Margaret in 1930 that astrology once again found widespread popularity. That year, the London Sunday Express ran an astrological profile of the princess to celebrate her birth -- and so began the modern newspaper horoscope column.
In the 1950s, French astrologers Michel and Françoise Gauquelin used sophisticated statistical studies to link the positions of the planets to human nature. Others, such as Dane Rudhyar, have expanded the study of Humanistic astrology.