Pietro Cavallini, The Apse of St. Paul Outside the Walls

19th century reconstruction (after the fire of 1823) of the 13th century original
Basilica of St. Paul Outside the Walls

In the upper register Christ presides from his throne and blesses the viewers with his right hand. The Greek letters that flank his halo are abbreviations for ΙΕCΥΟC ΧΡΙCΤΟC, "Jesus Christ." In the book he is holds are the words VENITE BENEDICTI PATRIS MEI | PERCIPITE REGNUM Q[UOD] V[OBIS] P[REPARATUM] A[B] O[RIGINE] M[UNDI], "Come, you blessed of my Father, accept the kingdom prepared for you since the beginning of the world" (Matthew 25:34). The Edenic nature of this kingdom is suggested by the fruited palm trees at the left and right, which are repeated in the lower band, and by the profusion of plants and animals in the land on which the figures stand.

The four figures flanking the throne are (left to right) St. Luke, St. Paul, St. Peter, and St. Andrew. Each is identified by an inscription in Latin. Hair and beard styles also characterize Paul, Peter, and Andrew; and Peter is further identified by his keys. The small white figure bowing at Christ's right foot is Pope Honorius III, who ordered the work on the apse.

The whole composition, and especially the phrases on the scrolls, aims at establishing the divinity of Christ. St. Paul's scroll reads, 🞣 in nomine i[es]u omne genu flectatur caelestium ter[r]estrium et infernorum, "in the name of Jesus every knee should bow, of those that are in heaven, on earth, and under the earth" (Philippians 2:10). St. Peter's scroll quotes his words to Jesus at Matthew 16:16, tu es xpc filius dei vivi, "Thou art Christ, the Son of the living God." St. Andrew's scroll adds the witness of a martyr that praying to Jesus is praying to God: beatus andreas penderet in cruce deprecantur d[omi]num iesum cr[i]st[um], "Blessed Andrew hung on the cross praying to the Lord Jesus." Above the throne, the half-circle with three bands of color completes the theme by suggesting the Trinity.

In the band below the anthropomorphic image of Christ, twelve apostles flank a second throne on which Christ is represented by a cross and the instruments of his Passion (the crown of thorns, Longinus's spear, a chalice with three nails, and the sponge). The angels flanking the throne hold scrolls reading gl[ori]a in e[x]celsis and et in terra pax, "Glory in the highest" and "And peace on earth." At the center of the cross is tiny image of anthropomorphic Christ. The jeweled cross, the enthroned Christ above, and the symbol of Trinity at the summit together form a vertical axis in which God himself is witness to the simultaneous divinity and humanity of Christ, while the four saints form a horizontal axis of human witness to the same reality.

The Apostles on the left of the jeweled cross are Barnabas (subbing for Peter, who is pictured above), Jude Thaddeus, James the Greater, Matthew, Philip, and John:

And on the right the Apostles pictured are James the Less, Bartholomew, Thomas, Simon, Matthias, and Mark (subbing for Andrew).

View the images of Christ Enthroned, the jeweled cross, and the Apostles on the left and right in full resolution.
Also see a perspective view of the apse and triumphal arch seen from the west end of the nave.
Read more about the Christ in majesty and the apostles as a group.
Read more about the Apostles and Evangelists:

Photographed at the basilica by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.