Built between the 12th and 13th centuries, it houses the Mazzatosta Chapel, frescoed by the painter Lorenzo da Viterbo and completed in 1460. The floor in front of the Chapel’s altar is covered with glazed ceramics. The floor’s primary colour is cobalt blue on a white background. Light yellow, copper green and manganese are also present. It depicts animals, flowers, leaves and anthropomorphic figures, which can be identified with real people from the community. The coats of arms of the Mazzatosta family and of Viterbo stand out.