The stars are like letters which inscribe themselves at every moment in the sky. Everything in the world is full of signs. All things depend on each other. As has been said, 'Everything breathes together.' (Plotinus)
All very nice, but scientific? Nonsense, you retort. Well, it is the oldest profession, mother of all our sciences. Until the 17th century, astrology was considered a scholarly tradition, and it helped drive the development of astronomy.
It was originally for the ruler and his wars and lineage. Only with the gradual emergence of horoscopic astrology, from the 6th c BC, were the techniques and practice of natal astrology developed. Ptolemy's work the Tetrabiblos laid the basis of the Western astrological tradition, and 'enjoyed almost the authority of a Bible among the astrological writers.' Ptolemy was so obsessed with getting horoscopes right that he began the first attempt to make an accurate world map (maps before this were more relativistic or allegorical) so that he could chart the relationship between the person's birthplace and the heavenly bodies. While doing so, he coined the term geography. Yet Cicero's De divinatione (44 BCE) rejects astrology and other allegedly divinatory techniques.