After Rome conquered the city in 88 B.C., Strabòne exclaimed admiringly, "AT TE CORFINIUM CIRCUMDATA VALIDIS MÙRIS," referring to the impressiveness of the defensive walls, of which few traces remain today. 

In the first century B.C., the territories of the Pelìgni were part of Rome's IV Regio, and the war, also known as "Màrsica" among writers of the time, became universally known as the "Social" War. A dispute was fought between Rome, in full expansion, and its most important Italic allies who claimed the right to become Roman citizens.

In February 49 B.C., after crossing the Rubicòne, Julius Caesar decided to ignore Rome and march quickly south to reach Pompéo. However, his rival managed to escape across the Adriatic Sea bound for Brindisi. It was at Corfinium that Caesar received reinforcement from the eighth legion and 22 cohorts recruited from Transalpine Gaul. Here he defeated Lucius Domitius Enobárbo after a short siege. On this occasion, Caesar forbade the sacking of the city and, in a surprising gesture, returned to the enemy the six million sesterces that Enobarbus had with him for the remuneration of the legions. This act was intended to show that "his disinterestedness" was "no less than his clemency." Most of the besieged joined the rebels, spreading the fame of the "Clemency of Corfinium" in the following days.