Its name derives from the pons curvus, "curved bridge", that may still be seen spanning the Liri in the center of the town that grew around the bridgehead in the course of the Middle Ages.

The medieval commune dates from 860, when Rodoaldo, the Lombard gastaldo of Aquino, erected the first version of the walled fortification on the rocca, intended to guard the bridgehead from Saracen intruders coming up the Liri.

The castle's chapel seems to have been dedicated to Saint Bartholomew; on the ruins of the Lombard castello was erected the earliest Cathedral of San Bartolomeo of which the campanile was a rebuilding of the castellan's tower.

The little bridgehead settlement formed part of the County of Capua; there in 866 Louis II, Holy Roman Emperor, set up camp at Pontecorvo in campaigns against the Saracens.

The first communal statute, among the earliest in the Kingdom of Naples, was granted in 1190, signalling a new era of civic self-confidence in a period in which Pontecorvo was briefly conquered and ruled by Roger II of Sicily, was claimed by the papacy, and was sacked by Charles of Anjou.