Church of San Pietro ad Oratorium

It lies at about six kilometers from Capestrano, direction Bussi sul Tirino. Of the ancient cenoby, founded in the 8th century and belonging to S. Vincenzo al Volturno Monastery, only the structure of the church rebuilt in the 12th century remains. According to the inscription you can read on the architrave of the entrance portal, the Lombard King Desiderius contributed to the foundation of S. Pietro ad Oratorium: "A Rege Desiderio fundata Milleno Centeno renovata". A monastery depending on the powerful abbey of S. Vincenzo al Volturno, it used to control a large estate consisting of Tritana Valley. The monastic settlement is situated in the point where the valley becomes narrow, not far from the ancient track of Claudia Nova and from river Tirino, both important ways of communication.

The management and control of such a large estate was not that easy, and the Chronicon talks about various rebellions by the valley inhabitants between the 8th and 9th century: they demanded freedom from the servile services they owned to the Monastery. In the 15th century, abandoned by the monks, it became Commandry of the Orsini family and, later, of the Piccolomini family.
The plan has a nave and two aisles, each ending with an apse. Inside, the structure is characterized by the presence of round arches on squared pillars. The presbytery, in a slightly raised position, houses a 13th-century ciborium. The apse is characterized by 12th century frescoes representing Christ and the 24 Old Man of the Apocalypse.
The façade shows the original stone-built wall surface consisting of isodomic segments up to the height of the lateral aisles. There is only one entrance portal with architrave decorated with vegetable patterns. On the façade, the famous and mysterious magic square with the sentence: SATOR AREPO TENET OPERA ROTAS.