The Baroque style Cattedrale di SanPietro (Cathedral of San Pietro) dates back to the 13th century, but in the first version it was a small chapel named after San Pietro. After being chosen as the cathedral of the town diocese in 1572, it was renovated and enlarged, as it looks like nowadays; but some signs of the original building are still visible on the facade and on the right side of the church.

The main treasure inside the cathedral is a Roman sarcophagus in polychrome marble known as “Sant'Eugenio's Ark”, because it was used as the patron saint's relics. The current aspect of this sarcophagus is the result of some restorations made between the 15th and the 16th centuries. Also noteworthy are the bishop's chair in carved walnut wood , the pulpit and a processional case in polychrome wood.