Aletrium (mod. Alatri), town of the Hernici 70 km. (43 mi.) south-east of Rome. Always loyal to Rome after 358 bce, Aletrium became a prosperous municipium (Cic. Clu.46) and remained such (reject Lib. colon.23). Its massive polygonal walls have survived almost intact, those surrounding the citadel being particularly remarkable. There is also an early aqueduct of c.100 bce, built by L. Betilienus Varus.