St. Gregory the Great, one of the Four Doctors of the Western Church (others St. August, St. Ambrose and St. Jerome), was born in Rome around 540 AD, he became Benedictine abbot of the monastery he founded on his family's land. In 590 he became Pope. St. Gregory was a reformer (particularly in matters of liturgy), philosopher and theologian, author of numerous works which had profound influence on medieval thought.
See: Dionysius. St. Gregory the Theologian.
Francisco de Goya. St. Gregory.
Peter Paul Rubens St. Gregory, St. Maurus, St. Papianus and St. Domitilla.
The Book of Saints: The Lives of the Saints According to the Liturgical Calendar by George Angelini, Victor Hoagland (Editor). Regina Press, Malhame & Company, 1986.
365 Saints: Your Daily Guide to the Wisdom and Wonder of Their Lives by Woodeene Koenig-Brick (Author). Harper SanFrancisco, 1995.