Saint Anselm of Canterbury (c. 1033 – 21 April 1109), also called Anselm of Aosta for his birthplace, and Anselm of Bec for his home monastery, is a Benedictine monk, philosopher, and prelate of the Church, who holds the office of Archbishop of Canterbury from 1093 to 1109.

Called the founder of scholasticism, he has been a major influence in Western theology and is famous as the originator of the ontological argument for the existence of God and the satisfaction theory of atonement.

Born into the House of Candia, he enters the Benedictine order at the Abbey of Bec at the age of 27, where he becomes abbot in 1079.

He becomes Archbishop of Canterbury under William II of England.

He is exiled from England from 1097 to 1100, and again from 1105 to 1107 (under Henry I of England), as a result of the investiture controversy, the most significant conflict between Church and state in Medieval Europe.

Anselm is proclaimed a Doctor of the Church in 1720 by a Papal Bull of Pope Clement XI.

His feast day is April 21.