The Crowned Head of David: Within the frame of medallions surrounding the Transfiguration, the bust of David occupies a focal position on the central axis with the cross. His purple cloak and jewel-studded crown emphasize not only his kingship but show him in the guise of a contemporary Byzantine emperor. Although the mosaicist sought to convey, primarily, the impression of Biblical king and prophet, the beardless David is thought to allude also to Justinian, the living emperor, who appears beardless in two other contemporary mosaics.