ANSELM (c. 1033–1109), Benedictine theologian, doctor of the church, archbishop of Canterbury, and Christian saint. Anselm is best known for an ontological argument for the existence of God that is still debated and for his opposition to the English kings William Rufus (William II) and Henry I on matters of ecclesiastical rights.

Born of a wealthy Lombard family in the Alpine village of Aosta in Piedmont, northern Italy, Anselm received his earliest education first from a relative and then from the local Benedictines. After the death of his mother in 1056, he gave up his patrimony and crossed the Alps with a companion in search of learning. In 1059 he made his way to the Benedictine abbey of Bec in Normandy (founded around 1039 by the abbot Herluin), where the learned and famous Lanfranc, a fellow Lombard from Pavia, taught. During the following year, at the age of twenty-seven, Anselm was persuaded...