Rulers reigned supreme, their ideas were not to be challenged.  They had their courtiers and advisers. One such adviser were court philosophers which included an astrologer. Most astrologers followed the ideas of Aristotle, a geocentrist. Geocentricity, the philosophy that Earth was the center of the universe, offered a comforting sense of the stability to leaders of many empires.  But others challenged this idea starting with Aristarchus, a contemporary of Aristotle.  These philosophers believed the Sun was the center.  This idea enticed Copernicus and led to a revolution of ideas that led to the Age of Revolution. Please comment on the differences between the Geocentric and Heliocentric Universes with this article.