Anselm of Canterbury (circa 1033-1109), also called of Aosta for his birthplace, and of Bec for his home monastery, was a Benedictine monk, a philosopher, and a prelate of the church who held the office of Archbishop of Canterbury from 1093 to 1109. Called the founder of scholasticism, he is famous as the originator of the ontological argument for the existence of God. Anselm was proclaimed a Doctor of the Church in 1720 by Pope Clement XI. Although utterly convinced of the truth of Christianity, Anselm of Canterbury struggled to make sense of his religion. He considered the doctrines of faith an invitation to question, to think, and to learn, and he devoted his life to confronting and understanding the most elusive aspects of Christianity. In Proslogium, his writings on matters the existence of God and His divine qualities make Anselm one of the greatest theologians and philosophers in history.