The deepest philosopher of the patristic era and one of the greatest theological geniuses of all times was St. Augustine (354-430), whose influence shaped the Middle Ages.Main works: Confessions, autobiography written between 397 and 400, one of the masterpieces of universal literature; The City of God, apology of Christian antiquity and essay of philosophy of history; De Trinitate; Enchiridion, compendium of Christian doctrine; various controversial works against the heresies mentioned, among which Against Faustum, De spiritu et littera, De natura er gratia, De gratia et libero arbitrio, De correptione et gratia, De praedestinatione sanctorum; exegetical works, such as Enarrationes in Psalmos, De genesi ad litteram, Treatise on the Gospel of St. John; pastoral works, such as De catechizandis rudibus; about 400 sermons and many letters.