The Agony And The Ecstasy filmed at Piazza del Popolo, Todi. This Umbrian square was dressed to look like St Peter's Square as it stood in 1508. On screen it's St Peter's Square.
Probable Named in published production coverage; the coordinate is the place itself, checked against a gazetteer.
Planning the trip? The Italy travel atlas covers money, language and getting around
Venture keeps every scene location on one map, sorted by how far you'd have to walk. Open it in Todi and it tells you what was shot around you, how to get there, and whether you can actually go in.
Download Venture for iOS Android