The Emperor Augustus chose Ravenna for one of his two naval stations, and in course of time a new city arose by the sea-shore, which received the name of Portus Classis. Between this harbour and the mother city a third town sprang up, and was called Cæsarea. Time and neglect, the ravages of war, and the encroaching powers of Nature have destroyed these settlements, and nothing now remains of the three cities but Ravenna. It would seem that in classical times Ravenna stood, like modern Venice, in the centre of a huge lagune, the fresh waters of the Ronco and the Po mixing with the salt waves of the Adriatic round its very walls.
