MISENUM, an ancient harbour town of Campania, Italy, about 3 m. S. of Baiae (<?..) at the western extremity of the Gulf of Puteoli (Pozzuoli). Until the end of the Republic it was dependent on Cumae, and was a favourite villa resort. Agrippa made the fine natural harbour into the main naval station of the Mediterranean fleet, and founded a colony there probably in 31 B.C. The emperor Tiberius died in his villa here. Its importance lasted until the decline of the fleet in the 4th century A.D. It was at first an independent episcopal see: Gregory the Great united it with that of Cumae. In 890 it was destroyed by the Saracens. The name was derived from one of the companions of Ulysses, or from Aeneas' trumpeter, an account of whose burial is given in Virgil, Aeneid, vi. 232.
The harbour consisted of the outer basin, or Porto di Miseno, protected by moles, of which remains still exist, and the present Mare Morto, separated from it by a comparatively modern embankment. The town lay on the south side of the outer harbour, near the village of Miseno, where remains of a theatre and baths and the inscriptions relating to the town have been found. Remains of villas can also be traced, and to the largest of these, which occupied the summit of the promontory, and belonged first to Marius, then to Lucullus, and then to the imperial house, probably belongs the subterranean Grotta Dragonara. Roads ran north to Baiae and north-west past the modern Torre Gaveta to Cumae: along the line of both are numerous columbaria.
See J. Beloch, Campanien, ed. ii. (Breslau, 1890), 190 sqq. (T. As.)