Formerly a dining hall and later a wash-house for the ancient Dominican monastery, the building dates back to the second half of the 1200s (enlarged in the fourteenth and seventeenth centuries) and exhibits a cycle of frescoes from the twelfth, fourteenth and sixteenth centuries (stories of the Virgin and Christ). The structure unearthed during the last restoration provides the backdrop for antique stained glass windows of the facade and part of the original trussed ceiling in frescoed terracotta.