William of Champeaux, born at Champeaux near Melun, was perhaps a student of Anselm of Laon. William was held in high esteem by his contemporaries for his mastery of grammar, logic, and rhetoric, as well as for theological speculations. By 1100 he was the Master of the Cathedral School associated with Notre Dame in Paris, the most prestigious position available for a philosopher; he held the rank of archdeacon, and was a confidante of Philip I. In this period Peter Abelard was first William's student and then his rival in public debates over philosophy. In 1108, William entered the Abbey of St. Victor newly established outside the walls on Paris, on the south bank of the Seine, and apparently continued to teach while there. In 1114 William was made bishop of Châlons-sur-Marne, a position he held until his death there in 1121.

William's...