Casilinum was an ancient city of Campania, Italy, situated some 3 miles north-west of Capua. The position of Casilinum at the junction of the Via Appia and Via Latina, at their crossing of the river Volturnus by a still-existing three-arched bridge, gave the town considerable strategic importance during the Roman Republic. Casilinum eventually lost its independence and became a praefectura. Caesar founded a colony at the town in 59 BCE, which was subsequently renewed by Mark Antony in 44 BCE. The veterans settled within the town took the side of Octavian after Caesar's death.