The Roman presence in Monte San Biagio's territory is testified by the presence of a mausoleum attributed to Emperor Galba, a native of the area, but which probably belonged to Sextus Iulius Frontinus, who had a great villa in the vicinity. The Romans defeated the Samnites here, at the Passo della Portella: in the place a fortified gate was built, which was later used as the border customs of the Kingdom of Naples. Nearby is a watchtower from the period of Pope Sixtus V.
