Built in the late Romanesque style, it has a black and white striped facade with ogival portals and a large rose window in enamelled terracotta. Restoration work was carried out between 1342 and 1350 but some parts from early Christian times are still visible. Inside, the central vault is decorated with some notable frescoes and there are two large confessionals in carved wood and an impressive marble baptistery. There is a fine polyptych on the altar at the end of the south nave dedicated to John the Baptist.