Cathedral of Santa Maria Assunta (1130). Destroyed in a siege, was rebuilt under the reign of Mariano II. Of the original structure remain only the apse and base of the tower and the chapel of the remedy, which houses some medieval sculptures.
In 1733 the 13th century Gothic Cathedral was demolished to make way for a Baroque. The 17th-century reconstruction of the chapel of the Archivietto. Inside the relics of Sant'Archelao.