This church is at the end of a deserted square, on the site of the Etruscan acropolis. It has a magnificent facade in golden stone dating from the 13C and in which the Evangelists' symbols enclose a rose window from the Umbrian school. The interior was built in the 11C by the masons from Lombardy. There are massive columns supporting curious denticulated arches. In the crypt is a veritable forest of small, all different columns from various eras that support groined vaulting.