It was not, however, till Octavianus, his enemies one and all disposed of, had made himself emperor at last, that, on the establishment and general regulation of his great government, he chose Ravenna as the major naval port of Italy upon the east, even as he chose Misenum upon the west. Octavianus had learned two things, certainly, in the wars he had fought to establish himself in the monarchy his great-uncle had founded. He had learned the necessity and the value of sea power, and he had understood the unique position of Ravenna in relation to the East and the West. That he had been able to appreciate both these facts is enough to mark him as the great man he was. Julius Caesar, for all his mighty grasp of reality, had not perceived the enormous value, nay the necessity, of sea power, and because of this failure his career had been twice nearly cut short; at Ilerda, where the naval victory of Decimus Brutus over the Massiliots alone saved him; and at Alexandria. Both the liberators and Antony had possessed ships; but both had failed to use them with any real effect. It was Sextus Pompeius who forced Octavianus to turn to the sea, and when Octavianus became Augustus he did not forget the lesson. Sole master of the Mediterranean and of all its ships of war, he understood at once how great a support sea power offered him and his principate. Nor was the empire, while it was vigorous, though always fearful of and averse from the sea, ever to forget the power that lay in that command. Thus it was that among the first acts of Augustus was the establishment of two fleets, as we might say, "in being" in the Mediterranean; the fleet of Misenum and the fleet of Ravenna; the latter with stations probably at Aquileia, Brundusium, the Piraeus, and probably elsewhere. The fleet of Ravenna was, certainly after A.D. 70, probably about A.D. 127, entitled _Praetoria_. The origin of this title is unknown, but it was also borne by the fleet of Misenum and it distinguishes the Italian from the later Provincial fleets, the former being in closer relation to the emperor, just as the Praetorian cohorts were distinguished from the legions. The emperor was, of course, head of all the fleets, which were, each of them, commanded by a prefect and sub-prefect appointed by him; and if we may judge from the recorded promotions we have, it would seem that the Misenate prefect ranked before the Ravennate and both before the Provincial. But in the general military system the navy stood lowest in respect of pay and position. The fleets were manned by freed men and foreigners who could not obtain citizenship until after twenty-six years' service. We find Claudius employing the marines of the _Classis Ravennas_ to drain lake Fucinus, and it was probably Vespasian who formed the Legion II. _Adjutrix_ from the Ravennate, even as Nero had formed Legion I. _Adjutrix_ from the Misenate marines.