Located in the cathedral ambulatory, the museum provides a significant overview of Val d’Aosta art between the 13th-18th centuries, combining pieces from the Cathedral’s rich treasure with works of art originating from different parishes in the Valley. 

The most precious examples include a chimney from the Roman era with precious stones and pearls set in a gold frame from the 13th century, used as a cope buckle; the unique pieces include the diptych of Honorius, testimony of late Roman art. 

Among the important Gothic sculptures are a wooden paliotto sculpted in the 13th-14th century.

The rich gold collection contains French items of Limousin art, precious silver relic busts with inscriptions and set with crystals and precious stones. Outstanding pieces include the large relic chest of Saint Gratus, which was created by William of Locana and, after his death, was entrusted to the Flemish sculptor Jean de Malines.

The museum holds a collection of marble sepulchral sculptures, 15th-century productions of the Val d’Aosta artist Stefano Mossettaz.