The navy maintained by the emperors might seem inadequate to their greatness; but it was fully sufficient for every useful purpose of government. The ambition of the Romans was confined to the land; nor was that warlike people ever actuated by the enterprising spirit which had prompted the navigators of Tyre, of Carthage, and even of Marseilles, to enlarge the bounds of the world, and to explore the most remote coasts of the ocean. To the Romans the ocean remained an object of terror rather than of curiosity; the whole extent of the Mediterranean, after the destruction of Carthage, and the extirpation of the pirates, was included within their provinces. 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. To all these we add the fleet which preserved the communication between Gaul and Britain, and a great number of vessels constantly maintained on the Rhine and Danube, to harass the country, or to intercept the passage of the barbarians. If we review this general state of the Imperial forces; of the cavalry as well as infantry; of the legions, the auxiliaries, the guards, and the navy; the most liberal computation will not allow us to fix the entire establishment by sea and by land at more than four hundred and fifty thousand men: a military power, which, however formidable it may seem, was equalled by a monarch of the last century, whose kingdom was confined within a single province of the Roman empire.