The policy of the emperors was directed only to preserve the peaceful dominion of that sea, and to protect the commerce of their subjects.

With these moderate views, Augustus stationed two permanent fleets in the most convenient ports of Italy, the one at Ravenna, on the Adriatic, the other at Misenum, in the Bay of Naples.

Experience seems at length to have convinced the ancients, that as soon as their galleys exceeded two, or at the most three ranks of oars, they were suited rather for vain pomp than for real service.
Augustus himself, in the victory of Actium, had seen the superiority of his own light frigates (they were called Liburnians) over the lofty but unwieldy castles of his rival.

Of these Liburnians he composed the two fleets of Ravenna and Misenum, destined to command, the one the eastern, the other the western division of the Mediterranean; and to each of the squadrons he attached a body of several thousand marines.

Besides these two ports, which may be considered as the principal seats of the Roman navy, a very considerable force was stationed at Frejus, on the coast of Provence, and the Euxine was guarded by forty ships, and three thousand soldiers.