In 65 AD, a native Syrian who lived in the Levantine coast of Lebanon, known by his Greek name of 'Dorotheus of Sidon', published an astrological compendium, which covered Natal, Horary and Electional astrology.

He was recognized as a major authority by classical and medieval astrologers both in the Christian and Arab worlds.

Dorotheus' principle impact on the Greeks was an irrevocable shift towards horary interrogations. His methods were used by all astrologer greats.

Michael Scot, astrologer for the Roman emperor Frederick II, would cast horary charts for his master. Thus, the foremost scholar in Europe was advising the most powerful man of time on the basis of the rules for celestial analysis set down twelve hundred years earlier by Dorotheus of Sidon.

Western astrology owes much to Ptolemy of Alexandria(125 AD), the Greek encyclopedian. He was a boyhood friend of Alexander the Great.

He compiled almost all the Chaldean and Egyptian astrology and astronomy known at the time, of which modern western astrology is based upon. The Nabataean Arabs (in southwest Jordan), through their trade with the Greeks, played a critical role in facilitating this information to Ptolemy.

Eventually, Alexander the Great gave rulership of Egypt to . He made Alexandria a great center of learning throughout the Hellenistic age, housing the world's biggest library with 500,000 volumes and a research Museum which attracted the leading scholars in the world. Unfortunately, it was burnt by the Romans during one of their invasions to Egypt in 48 BC.