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.