Detail of the Byzantine apse mosaic (c.530) in Santi Cosma e Damiano, Rome. At the bottom of the mosaic is the Lamb of God with a silver halo, surrounded by 12 sheep symbolizing the apostles. The Lamb stands on a hill with Bethlehem on the right and Jerusalem on the left, and the four rivers of Paradise (labeled GION, PISON, TIGRIS, EVFRATA) flow down from it. Beneath the sheep is the dedicatory inscription: "This hall of God shines in its adornment with enamels, a hall where the precious light of faith gleams even more brightly. To the people a sure hope of salvation comes from the martyrs who heal their ills, and the temple before named as sacred has increased in honor. Felix has made to the Lord this offering, worthy of the Lord's servant that he may be granted life in the airy vault of heaven."