of the first Punic war enables us to solve what, until Mahan wrote, had been one of the standing enigmas of history, viz.  Hannibal’s invasion of Italy by land instead of by sea in the second Punic war.  Mahan’s masterly examination of this question has set at rest all doubts as to the reason of Hannibal’s action.[21] The naval predominance in the western basin of the Mediterranean acquired by Rome had never been lost.  Though modern historians, even those belonging to a maritime country, may have failed to perceive it, the Carthaginians knew well enough that the Romans were too strong for them on the sea.  Though other forces co-operated to bring about the defeat of Carthage in the second Punic war, the Roman navy, as Mahan demonstrates, was the most important.  As a navy, he tells us in words like those already quoted, ’acts on an element strange to most writers, as its members have been from time immemorial a strange race apart, without prophets of their own, neither themselves nor their calling understood, its immense determining influence on the history of that era, and consequently upon the history of the world, has been overlooked.’

[Footnote 18:  R. S. Whiteway, Riseof_the_Portuguese_Power_ inIndia_ p. 12.  Westminster, 1899.]

[Footnote 19:  J. H. Burton, Hist.of_Scotland_, 1873, vol. i. p. 318.]

[Footnote 20:  Mommsen, i. p. 427.]

[Footnote 21:  Inf.on_Hist._, pp. 13-21.]

The attainment of all but universal dominion by Rome was now only a question of time.  ’The annihilation of the Carthaginian fleet had made the Romans masters of the sea.’[22] A lodgment had already been gained in Illyricum, and countries farther east were before long to be reduced to submission.  A glance at the map will show that to effect this the command of the eastern basin of the Mediterranean, like that of the western, must be secured by the Romans.  The old historic navies of the Greek and Phoenician states had declined.  One considerable naval force there was which, though it could not have prevented, was strong enough to have delayed the Roman progress eastwards.  This force belonged to Rhodes, which in the years immediately following the close of the second Punic war reached its highest point as a naval power.[23] Far from trying to obstruct the advance of the Romans the Rhodian fleet helped it.  Hannibal, in his exile, saw the necessity of being strong on the sea if the East was to be saved from the grasp of his hereditary foe; but the resources of Antiochus, even with the mighty cooperation of Hannibal, were insufficient.  In a later and more often-quoted struggle between East and West—­that which was decided at Actium—­sea-power was again seen to ‘have the casting vote.’  When the whole of the Mediterranean coasts became part of a single state the importance of the navy was naturally diminished; but in the struggles within the declining empire it rose again at times.  The contest of the Vandal Genseric with Majorian and the African expedition of Belisarius—­not to mention others—­were largely influenced by the naval operations.[24]