Judicial astrology in theory and practice in later medieval Europe

Interrogations and elections were two branches of Arabic judicial astrology made available in Latin translation to readers in western Europe from the twelfth century. Through an analysis of the theory and practice of interrogations and elections, including the writing of the Jewish astrologer Sahl b. Bishr, this essay considers the extent to which judicial astrology was practiced in the medieval west. Consideration is given to historical examples of interrogations and elections mostly from late medieval English manuscripts. These include the work of John Dunstaple (ca. 1390–1453), the musician and astrologer who is known have served at the court of John, duke of Bedford. On the basis of the relatively small number of surviving historical horoscopes, it is argued that the practice of interrogations and elections lagged behind the theory.