Montesarchio (Neapolitan: Muntesarchio; Latin: Caudium; Ancient Greek: Καύδιον, romanized: Kaúdion) is a comune in the Province of Benevento, Campania, Southern Italy.

It reappears at a later period as a small town situated on the Appian Way, and apparently deriving its chief importance from the transit of travellers:[8] the same causes preserved it in existence down to the close of the Roman Empire.

[9] It received a colony of veterans; and it appears from Pliny, as well as from inscriptions, that it retained its municipal character, though deprived of a large portion of its territory in favor of the neighboring city of Beneventum.

After the fall of the Western Roman Empire, in the 7th century a Lombard nobleman called Arcolo founded a shelter and fought against Charlemagne.

Feudatories who held Montesarchio include, starting from the 13th century, D'Aquino, Della Leonessa, Caracciolo, Carafa and D'Avalos, who owned it until the abolition of feudality in 1805.