The Franciscan monastery of St. Francis dates from the 13th century and occupies a quiet spot near the old town, easy to miss between the louder monuments. The church has a simple single-nave Gothic interior with some good carved detail in the sacristy, which also holds a small but excellent collection of Roman glass, jewellery, and coins.
The cloister is the best part — a peaceful garden court surrounded by Romanesque-Gothic arcades, well preserved and rarely busy. The monastery is still active, and the cloister is accessible during church visiting hours. A good place to step off the tourist circuit for twenty minutes.