Christ, the Evangelists, and the Apostles
Basilica of San Vitale, Ravenna, Italy
This is the space above the main apse. At the top Christ is flanked by symbols representing the four evangelists (L to R: John's eagle, Matthew's angel, Mark's lion, Luke's ox). Below that register, lambs representing the twelve apostles process from the two cities left and right toward the Savior. In other mosaic compositions of the early centuries, cities placed in this way represent Bethlehem and Jerusalem.
This image in full resolution
More of the four evangelists
More of the apostles as a group
More of the lamb of God symbol
Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.