Built above an early Christian basilica, Sant'Orso collegiate church (named after an Irish monk who came to evangelise the valley in the 11C) has retained its beautifully sculpted wooden stalls from the 15C and a Baroque rood screen. Next to the 11C crypt, there is an entrance to a charming little Romanesque cloister with historiated capitals illustrating biblical or profane scenes. The priory is a Renaissance building with elegant windows.