John of Damascus

John of Damascus or John Damascene was a Christian monk, priest, and apologist. Born and raised in Damascus c. 675 or 676; the precise date and place of his death is not known, though tradition places it at his monastery, Mar Saba, near Jerusalem on 4 December 749.
A polymath whose fields of interest and contribution included law, theology, philosophy, and music, he was given the by-name of Chrysorrhoas.
He wrote works expounding the Christian faith, and composed hymns which are still used both liturgically in Eastern Christian practice throughout the world as well as in western Lutheranism at Easter.
He is one of the Fathers of the Eastern Orthodox Church and is best known for his strong defence of icons. The Catholic Church regards him as a Doctor of the Church, often referred to as the Doctor of the Assumption due to his writings on the Assumption of Mary.
He was also a prominent exponent of perichoresis, and employed the concept as a technical term to describe both the interpenetration of the divine and human natures of Christ and the relationship between the hypostases of the Trinity.