William of Auxerre (c.1140–1231), French theologian and renowned teacher of grammar, arts, and theology at the University of Paris. In 1231 he was appointed by Pope Gregory IX to a commission charged with editing Aristotle’s writings for doctrinal purity. The commission never submitted a report, perhaps partly due to William’s death later that same year. William’s major work, the Summa aurea (1215–20), represents one of the earliest systematic attempts to reconcile the Augustinian and Aristotelian traditions in medieval philosophy. William tempers, e.g., the Aristotelian concession that human cognition begins with the reception in the material intellect of a species or sensible representation from a corporeal thing, with the Augustinian idea that it is not possible to understand the principles of any discipline without an interior, supernatural illumination. He also originated the theological distinction between perfect happiness, which is uncreated and proper to God, and imperfect happiness, which pertains to human beings. William was also one of the first to express what became, in later centuries, the important distinction between God’s absolute and ordained powers, taking, with Gilbert of Poitiers, the view that God could, absolutely speaking, change the past. The Summa aurea helped shape the thought of several important philosophers and theologians who were active later in the century, including Albertus Magnus, Bonaventure, and Aquinas. William remained an authority in theological discussions throughout the fourteenth and fifteenth centuries. See also ARISTOTLE , AUGUSTIN. J.A.Z.