This is the old Church of the monastery founded in the 13C by the Franciscans. The facade of the current building, which is very large, (15C and 16C) is quite seductive with the fantasy in its flamboyant decor. The interior is surprising in its size and the skill in the vaulting arrangement. The lower room in the clock tower, the only remnant of the original Church, houses the Treasure: notice above all a Byzantine diptych in ivory from the 13C.