The patron saint of Valfabbrica is Saint Sebastian, celebrated on 20 January, in the Church-Museum dedicated to him. Built in the 14th century on the castle walls as a castle chapel, it was completely restructured in the 16th century, when the confraternities of the Santissimo Sacramento and the Buona Morte enlarged it, turning the interior into a three-nave space; further work in the 18th century gave it its present late Baroque appearance.
Behind the main altar is a panel with the Crucifixion, mourners and saints Sebastian and Francis, painted in the 1570s by Giovanni Maria Baldassini. Besides the main altar, the church preserves six others: the oldest, from the 17th century, dedicated to the Madonna del Rosario, retains from its original arrangement only the small paintings depicting the Mysteries of the Rosary at the sides of the altarpiece, two of which were later stolen. Today the church is also partly used as a museum.
