The three medallions on the left wing tell the story of Constantine's conversion to Christianity. Starting with the bottom medallion on the left wing, it pictures the medieval version of the legend of Constantine having a dream the night before the Battle of the Milvian Bridge, where he dreams an angel appears, points to the Cross, and tells him he will conquer under that sign. The middle medallion shows Constantine's victory at the Milvian bridge, with a cross standard. The upper medallion shows Constantine being baptized just before his death, by Pope Sylvester I, below an approving Hand of God.