First edition of the famous astrologer Abū Ma‘shar's (Albumasar, c. 787–886) De magnis coniunctionibus, translated into Latin probably by John of Seville. The Arabic original was known by titles including Kitāb fi duwal wa-al-milal (Book on Dynasties and Religions) and Kitāb al-qirānāt (Book of Conjunctions). This elaborate astrological interpretation of history, of Sassanian (Zoroastrian) origin, reached Abū Ma‘shar through the works of Māshā’allāh, al-Ṭabarī and al-Kindī. The book suggests that ever-changing planetary influences mean no human institution – be that religion or kingly power – can hold a permanent state. The book is in eight chapters: on the appearance of prophets and their laws, the rise and fall of dynasties and kings, the effects of planetary combinations, the effect of each zodiacal sign's being in the ascendant, the lordships of the planets, transits, each zodiacal sign as muntaha and as ascendant of the revolution of the year, and the revolution of the years. There are also significant passages on comets that influenced medieval Western writers.