(the ancient Arpium), a town of Naples, in the province of Terra di Lavoro, pleasantly situated on an eminence 6 miles south of Sora. It has a considerable trade, and manufactures woollen cloth, leather, parchment, and paper. In the vicinity is an extensive paper mill which gives employment to 200 persons. Pop. 11,000. This was a very celebrated city of the Volsci, and afterwards came into the possession of the Samnites, from whom it was taken by the Romans in B.C. 305. During the latter period of the Roman Republic it was a flourishing municipal town; but it is chiefly distinguished as the birthplace of two of the most illustrious men in Roman history, Caius Marius, and Marcus Tullius Cicero. The latter frequently alludes to Arpinum in his letters, and describes the inhabitants as rustic and simple in their manners, but possessing many virtues. His favourite villa was situated in a plain beneath the town, on the banks of the little river Fibrenus. Remains of the walls and of the ancient city are still to be seen.