The church of San Pietro, located on the hilltop of the same name in Tuscania, is an example of refined Romanesque-Lombard art. With an impressive presentation, consisting of two watchtowers and its white façade, embellished with a rose window. A selection of Etruscan sarcophagi can also be admired in the courtyard. It is believed that the basilica, originally built in the 8th century, was built on the remains of a pagan temple. The surrounding ruins of the Etruscan-Roman acropolis.
Over the centuries, the church has undergone various architectural transformations. In the 11th century, the naves, apses and crypt were rebuilt, while in the early 12th century, the entrance to the nave was elongated with two arches. The façade has also undergone several interventions: the side parts built in the 12th century and, at the beginning of the following century, the central vertical body, protruding by about one metre from the side parts. During that period, the hill became a fortress and several defensive towers were built around the church and episcopal palace. Two of them are still part of the scenic arrangement, while a third, which has been cut off, is positioned in front of the façade outside the perimeter.