Traces of an important settlement of the ancient Samnites can be found on Monte Saraceno, a thousand metres above the Trigno valley and about a kilometre from Pietrabbondante. Parts of fortifications from the 4th century B.C. remain, dismantled by the Romans at the end of the third and last of the wars that were fought between the two peoples until Rome's victory.
Then, between the third and first centuries BC, the Samnites provided themselves, on one side of the mountain, with a majestic sanctuary, connected to a semicircular cavea like that of a theatre. It was clearly meant to reaffirm the identity of the beaten nation and provide a fundamental religious and political centre.
The most important core of the complex comprises, in addition to the cavea, two temples dating from distinct phases. Of the smaller temple, built at the beginning of the second century BC, the podium remains. Instead, the main temple and the cavea are part of a unitary project carried out between the 2nd and 1st century BC: they were built on the remains of a building that Hannibal's Carthaginians had destroyed in the meantime during their war of invasion. The Samnites, in fact, had agreed to become partners with Rome after the defeat.
Particularly well preserved is the cavea, the so-called Theatre: built towards the end of the second century BC, it is thought to have served as a place for assemblies. Behind it is the main temple, completed at the beginning of the first century B.C.: its imposing podium and two of the three areas preceding the steps leading to the pronaos are preserved.
In 2002, a building on the south-west terrace of the complex was identified, built towards the end of the second century BC – the so-called "Domus publica" – probably intended as the seat of the Samnite nation's high magistrate and for ritual activities during religious festivals.