The Lamb of God
Dating suggestions vary from the 8th to 11th centuries
Protyrum (see photo) of the Basilica of Santa Pudentiana, Rome
The inscription reads HIC AGNUS MUNDUM RESTAURAT SANGUINE LAPSUM . MORTUUS ET VIVUS IDEM SUM PASTOR ET AGNUS, "Here the Lamb restores the fallen world. Both dead and alive I am shepherd and sheep." The second sentence could be a reference to the name of St. Pastor, which means "shepherd" and who is represented on this same frieze.
More of the Symbols of Christ
Photographed at the basilica by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.