In Iran, and indeed throughout the ancient world, people were fascinated with the stars and planets that filled the night sky. Careful study of the motions of planets was well established in Mesopotamia by the 3rd millennium BC. Babylonian astronomers became particularly proficient in the practice, using mathematical formulas to map and predict astral movements and keeping detailed records on clay tablets, some of which survive. These scholars observed the stars to help understand and predict the times for harvest, natural disasters, and even the rise and fall of political powers.

When the Achaemenid kings conquered Babylon in the 6th century BC, they allowed Babylonian astrologers to continue working without interruption. Astronomers travelled with the Iranian king to provide him with horoscopes and celestially-informed advice. As the centuries progressed, Ancient Iranian astronomy was further refined by dialogue with the astrological traditions of India and the Greco-Roman world.  Five branches of astronomy had emerged by the time of the Sasanian Empire:

  • Genethialogy: predictions about individuals based on the Zodiac
  • Astrological history: recording of the rise and fall of rulers, dynasties, governments, and religions
  • Catarchic analysis: guidance for followers towards choosing a time to begin certain activities
  • Interrogations: astrologers posing questions to themselves, a sort of philosophical rhetoric
  • Iatromathematics: applying astrological doctrines to medical practice

Astrology continues to fascinate today, and has recently enjoyed a resurgence in Western culture, but in Ancient Iran it was more pervasive and taken far more seriously, combining what we would describe as astronomy – a sophisticated system for observing the stars and other celestial phenomena – and the belief that the stars communicate divine truths.