Inaugurated in 1929, the museum collects the Treasure of the distinguished Basilica of Santa Maria Assunta (1423), rebuilt in the early seventeenth century in Baroque forms. Among the numerous sacred art objects, the so-called Cross of Matrenyanos de' Filippis from the fifteenth century, paintings and wooden sculptures (XV-XVII century), Flemish tapestries from the sixteenth century, furnishings, precious vestments (piviale, dalmatics, chasubles, canopies), monstrances, and chalices stand out. The museum includes the Nativity Scenes section, which now houses around 300 pieces and is considered one of the best in Italy in the sector. The section of textile industrial archaeology houses machinery from the eighteenth and nineteenth centuries that testify to the work of the Gandino weavers who produced woolen fabrics.