The Apse at Monreale Cathedral: Detail, the bottom register

Left to right, the saints are Martin, Stephen, Peter of Alexandria, Clement, Silvester, Thomas Becket, Lawrence, and Nicholas. They are all labeled, but little else distinguishes them from one another. The two deacon saints differ from the bishops in being beardless and wearing a sort of alb rather than the chasubles and pallia that signify the episcopal status of the others.

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More of St. Martin
More of St. Stephen
More of St. Clement
More of St. Thomas Becket
More of St. Lawrence
More of St. Nicholas

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