The Apse Mosaic at St. Paul Outside the Walls: Detail of the Cross Enthroned

Circa 1220
St. Paul Outside the Walls, Rome

In an echo of much earlier mosaics, Christ is represented by a cross, in this case enthroned as in Heaven. In the center of the cross is a tiny image of Christ himself, and below the crossbars are four of the instruments of the Passion: the crown of thorns, the spear of Longinus, a chalice with three nails, and the sponge.

The archangels flanking the throne hold scrolls with the first words of the phrases GLORIA IN EXCELSIS DEO (right) and ET IN TERRA PAX HOMINIBUS BONAE VOLUNTATIS (left) – "Glory to God in the highest, and on earth peace to men of good will."

View this image in full resolution.
Here is a long view of the apse in the basilica.
Read more about the Cross as symbol.

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