Ostia, anciently the port of Rome, from which it is six miles distant, was believed to have been founded by Ancus Martius, who also established salt-works here. Originally a trading port, it became in the Punic Wars a naval station, and its inhabitants were exempt, from military service.
Owing to the silting up of the lower Tiber, the Emperor Claudius caused a new harbour - which received the name "Portus" - to be constructed, and connected it with Rome by a canal. This soon rivalled Ostia, which gradually decayed, and was finally destroyed by the Saracens in the ninth century. Both places are now in ruins.