It is one of the most remarkable Carolinge churches in Italy dating back to the second half of the IX century.
It has a Latin cross-shaped plant with barrel vaults on the lateral and cruciate arms on the tibur. The cover is guaranteed by a dome set on columns intuitively inspired by the Ionic style through the volute relief design. This is why it is indicated as one of the most obvious examples in ancient rim recovery in Italy during the so-called Carolingian Renaissance.
Source: Wikipedia (Italian only)