a seaport-town of Latium, was, as its name implies, at the mouth of the Tiber, at the distance of 16 miles from Rome by the Via Ostiensis. It was founded by Ancus Marcius, and originally derived its importance from supplying salt to the neighbouring district. Becoming in course of time the port of Rome, it began to flourish simultaneously and proportionally with that city. In the second Punic war, merchant vessels with grain from Sicily and Sardinia, and ships of war for the protection of the coast, were wont to throng its harbour. It was also about the same time the seat of a quaestor, who was called Quaestor Ostiensis, and whose task was to provide Rome with corn. But all the while the mud brought down by the Tiber was filling up the harbour, and rendering it incapable of receiving large vessels. That another port should be made for the capital of Italy was accordingly seen to be necessary. On the shore, about 2 miles north from Ostia, a new basin, called the Portus Augusti, and communicating with the Tiber by means of an artificial canal, was dug by the Emperor Claudius; an inner basin, called Portus Traiani, was added by Trajan; and this double harbour came to be called Portus (Porto), and gradually drew away all the traffic from Ostia. That ancient town had thus reached its acme of prosperity. Although handsome public edifices were reared by successive emperors, it dwindled down by degrees, until in the middle ages it fell completely into ruins. These ruins have been left by the constantly advancing shore about 3 miles from the mouth of the Tiber. About half a mile further up the river is the modern Ostia, an insignificant village.