The Museo Diocesano di Lanciano collects religious art and objects from the local diocese. It is not a large museum, but it gives useful context to a town where churches are the main sights and faith has shaped the visitor route for centuries.
Look for sculpture, paintings, vestments, and liturgical pieces that once belonged to churches in and around Lanciano. The museum works best as a companion to the cathedral and Santa Maria Maggiore rather than as a standalone destination.