Pierre d'Ailly

Pierre d’Ailly, Cardinal (1351–1420).
Concordantia astronomiae cum theologia.
Augsburg: Erhard Ratdolt, 2 January 1490. (06014)

Cardinal Pierre d’Ailly was a leading French theologian and champion of church unity during the Papal Schism (1378–1414). In this treatise he sought to reconcile theology and the science of astronomy, which included astrology. D’Ailly argued that divine will was revealed in the stars, and that although human will remains free, the outcomes of earthly endeavors are subject to astrological influences that can be forecast – an idea that the Inquisition later branded as heretical. The book’s woodcut frontispiece shows a theologian and an astronomer in harmonious conversation beneath the heavenly spheres.