Archaeological Site of Colle di San Pietro Montagnon at Montegotto Terme: in the course of time, three big buildings (presumably built between the 1st century B.C. and the 2nd century A.D.) have been located in the area around Colle San Pietro Montagnon: the biggest one was discovered underneath the now existing Duomo dedicated to Saints Peter and Paul, a second one was found underneath the Oratorio della Madonna Nera, while a wide circular thermal pool – the so-called “Bagno di Montagnone” – emerged in the 19th century halfway between the aforesaid two structures. These buildings were all linked to the exploitation of thermal water: as a matter of fact, several lengths of pipes and stretches of Roman aqueducts have been found on a number of occasions all around the hill. The Oratorio della Madonna Nera was built in 1724 and became the parish church dedicated to St Peter until the mid-20th century, when the new Duomo was erected. The Oratorio exploits a belfry dating back to the 13th century.
The documentation about buildings, aqueducts and items found on the Colle di San Pietro Montagnon is the result of casual discoveries, occurred at various times in the past centuries; no building is visible any longer. In particular, the building with a series of adjacent rooms emerged in the Sixties; the so-called “Bagno di Montagnone” and the second thermal building were discovered at the beginning of the 19th century, together with mosaics and other structures located in the area today occupied by the Oratorio della Madonna Nera.