  William of Auvergne or Paris, (ca.1180/90–1249), Bishop of Paris from 1228 until his death in 1249, was one of the first wave of thinkers in the Latin West to engage with the writings on natural philosophy and metaphysics by Greek, Islamic and Jewish thinkers that had recently become available in Latin translation. William took these writings to pose errors dangerous to the Christian faith, and his philosophical works are in large part aimed at combating their errors. Yet at the same time he recognized their philosophical value and, though often confused about their meaning, incorporated their teachings into his own thought.  On many of the important issues of later medieval thought, William is the first to provide in-depth discussions, and his voluminous works are an important and still under-appreciated source for our understanding of the development of medieval philosophy.