In this area the Romans defeated the Samnites in 315 BC and, during the Second Punic War (219-202 BC), were able to block Hannibal.
The Roman Empire was invaded by the Lombards and Saracens, and for centuries the town followed the fate of the county of Fondi until the year 1140 when it became part of the Kingdom of Naples and given in fief to the Aquila family. Later it passed under the control of the Caetani family (1299), Colonna (1494), Gonzaga (1570), Carafa (1591), Mansfeld (1690) and Di Sangro (1721).
Its original name Monticelli was changed after the unification of Italy and the name was chosen in honour of the patron saint.
Through here passes the border between the Papal State and the Kingdom of the Two Sicilies, in the locality Epitaffio named so by an inscription of the XVI century, and this was a customs checkpoint.
Between the sixteenth and seventeenth century it was plagued by a serious crisis due to the resurgence of malaria in the Fondi plain that was being invaded by marshes. In 1637 it was almost completely deserted and only returned ‘to life’ thanks to the reclamation started in 1639 by the Princess Anna Carafa.
Because of its location on the border of this area there were a lot of bandits after the unification of Italy and the last Bourbon garrison left here in November of 1860.