This is the story of Western astrology - that 'ancient art' which covers everything from a vague acceptance of stellar influences on the lives of men to precise and fatalistic predictions of the future. Astrology, science or art, came into existence with the discovery of a mathematical system which enabled men to plot the relative positions of earth and planets against the background of the fixed stars. The story begins in Greece, in the fifth century BC, with the absorption into Greece of protoastrological ideas from the east. The Greeks took stargazing and its magic and added philosophy, geometry and rational thought; the philosophy of Plato and later of the Stoics made astrology respectable, and by the time Ptolemy wrote his textbook the Tetrabiblos, in the second century AD, the main lines of astrological practice as it is known today had already been laid down.Jim Tester shows how little astrology changed during its journey from the Greek world through Islam and back into the West in the 12th century; even in the Renaissance and in the 17th century it preserved its conservative character, until it was seemingly killed by the shift of ideas in the late 17th and 18th century.
The revival of astrology in the 19th and 20th century is outside the scope of this study, but parallels between the ages of its greatest influence in the past - late antiquity and the Renaissance - and our own times are irresistible.