The Dome of the Mausoleum of Galla Placidia
Revelation 4:2, 6-8 tells of four winged creatures "round about the throne" of "the one sitting" in Heaven. Early Christian commentators interpreted these as the four evangelists, and artists followed suit by picturing them around a cross representing Christ. Here Heaven is suggested by the field of stars on a blue background, and the winged creatures are, clockwise from the upper left of this photograph, the lion of St. Mark, the ox of St. Luke, the eagle of St. John, and the "third living creature, having the face, as it were, of a man."
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View detail photographs of the eagle, the angel, the ox, and the lion.
Read more about the cross symbol and about images of the Evangelists.
Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.