The church of Saints Nereo and Achilleo is a 4th century basilica in Rome found close to the monumental ruins of the Baths of Caracalla. The proximity of the church to those ruins meant that the ecclesiastics could forage for loot, and found a huge porphyry urn and placed their pulpit on top of it. The mosaics date from the period of the papacy of Leo III, the early 10th century, showing here the Transfiguration of Christ.