After studying under Anselm of Laon and Roscellinus, he taught in the school of the cathedral of Notre-Dame, of which he was made canon in 1103.
[3] William left St Victor in 1113 when he became bishop of Châlons-en-Champagne, at which time he took part in the dispute concerning investitures as a supporter of Pope Callixtus II, whom he represented at the conference of Mousson.
After relinquishing his Benedictine Abbacy, he moved to a Cistercian monastery in Rheims, where he also composed a number of spiritual books, such as his Vita Prima, which were widely read in monastic circles.
[6] In the last of these he maintains that children who die unbaptized must be lost, the pure soul being defiled by the grossness of the body, and declares that God's will is not to be questioned.
[2] He is considered the founder of an early version of moderate realism, a philosophy which held that universals exist in particular things as common substances individuated by accidents and in the mind as concepts.