Anselm of Canterbury, Archbishop of Canterbury, dies in England. A medieval scholastic philosopher, Anselm of Canterbury was one the first to make extensive use of Aristotelian logic.
Thus some argue that Anselm was essentially the father of medieval scholasticism because he starts the trend of using Aristotelian terminology and concepts in defending Christian theology.
Anselm of Canterbury created one of the most famous formulations of the Ontological Argument (in his book Proslogian) for the existence of God (though it was not intended as a proof of God). According to Anselm, God is a "being than which no greater can be conceived" and since actually existing is greater than merely existing as a concept in the mind, God must really exist. If God was merely a concept, it would be possible to conceive of something greater — an actual God.
Using such linguistic analysis to solve some conceptual problems was characteristic for Anselm's writing and was not used solely in the ontological argument.