De magnis coniunctionibus by Abū Maʿshar
Abu Ma’shar, the great astrologer of Baghdad, was the most influential authority on astrology in medieval and Renaissance Europe. He wrote about forty treatises, several of which were translated from Arabic into Latin beginning in the twelfth century. This volume is about “The Great Conjunction” (De magnis coniunctionibus), or alignment of Jupiter and Saturn in the sky.