Born in Aosta in Northern Italy, Anselm became a Benedictine, and was Archbishop of Canterbury from 1093, although he spent many of the following years in exile. He staunchly defended the rights of the Church, and in theology the rights of reason, which he saw as a buttress to faith rather than a source of scepticism. His two principal theological treatises are the Monologion (‘Soliloquy’) and the Proslogion (‘Discourse’). The former contains versions of the cosmological argument and argument from the existence of goodness to the existence of a supreme good. The latter contains the famous ontological argument for the existence of God. Anselm also wrote many dialogues concerned with particular problems in logic and theology: De Veritate (‘Of truth’), De Libertate Arbitrii (‘Of free choice’), and De Grammatico contain linguistic and analytical investigations that justify his claim to be the father of scholastic philosophy. His Cur Deus Homo (‘Why was God man?’) interprets the atonement in terms of satisfaction due to the outraged majesty of God, which remains one of the main competing explanations available to Christian theology.

http://www.newadvent.org/cathen/01546a.htm A biography of Anselm