Traditio Legis Fragment
Museum of the Church of St. Paul Outside the Walls, Rome
The man on Christ's left appears to be St. Peter because of the short, square beard. He receives a scroll from Christ and holds something in his left hand that could be a fragment of a cross or a set of very large keys. The man on Christ's right (St. Paul?) is one of several holding rolled-up scrolls.
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Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.