The Transfiguration Mosaic at Sant'Apollinare in Classe

6th century
Basilica of Sant'Apollinare in Classe, Ravenna

This image is discussed in Margaret E. Frazier's "The Christian Realm: Apse Themes," in Weitzmann. The cross represents the transfigured Christ. To its left and right are Moses and Elijah, respectively. The figure below with the sheep is St. Apollinaris.

Detail photographs:

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Read more about images of Saint Apollinaris, the Transfiguration, and sheep as symbols in Christian art.

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