(Collecta: S. Pietro)
(Image source)
(Image source))
From the Churches of Rome wiki:
The church was built in the 5th century, according to tradition by Pope St Gelasius I (492-496). Maker's stamps on roof tiles have been dated to the end of the 5th century, so it seems likely that it was indeed built during St Gelasius' time.
It was rebuilt c. 720, and restored in 1191.
[...]
During the latest restoration, an archaeologist found 12th century paintings hidden by plaster. They depict scenes from Genesis, the Creation and the Fall of Man, and from the New Testament, the Redemption. The Old testament scenes start on the right side near the sanctuary, and the New Testament scenes are painted below them in two tiers.
In the central apse are 12th century paintings of the 24 Elders of the Apocalypse and symbols of the Evangelists.
Fragments of ancient sculptures have been reused in the pavement of the sanctuary and the narthex, and some of the pieces can be interesting.
The church has a triple apse in the Eastern style.
