Above the chapel arch is the famous fresco by Raphael of four Sibyls, those of Cumana, Persia, Phrygia and Tiburtina, each receiving a revelation from an angel. At the top a small angel with a burning torch indicates their importance; they are to serve as lights to the pagan world. In the Middle Ages, it was believed that the Sibylline Prophecies preserved in written form in ancient Rome contained prophecies of Christ. The influence of Michelangelo's work in the Sistine Chapel is obvious. Above is the Chigi coat-of-arms.