Saint Cyril of Alexandria championed the teaching concerning Christ’s one divine Personhood against Nestorius. He wrote extensively clarifying the doctrine concerning the Trinity, theological formulas, and the doctrine of Mary as Mother of God. He had a staunch adherence to the truth, yet, as Bishop of Alexandria, he was impulsive, imprudent, and sometimes harsh dealing with his flock and fellow bishops. He is known as the “Tower of Truth and interpreter of the Word of God made flesh.”