There is something more than mere literary interest in the fact that the term in another language was used more than two thousand years ago.  Before Mahan no historian—­not even one of those who specially devoted themselves to the narration of naval occurrences—­had evinced a more correct appreciation of the general principles of naval warfare than Thucydides.  He alludes several times to the importance of getting command of the sea.  This country would have been saved some disasters and been less often in peril had British writers—­taken as guides by the public—­possessed the same grasp of the true principles of defence as Thucydides exhibited.  One passage in his history is worth quoting.  Brief as it is, it shows that on the subject of sea-power he was a predecessor of Mahan.  In a speech in favour of prosecuting the war, which he puts into the mouth of Pericles, these words occur:—­ oimeu_ garouch_exousi
u_allaeu_autilabeiu_amachei_aemiu_de_esti_ gaepollae_kai_eu_uaesois_kai_kat_aepeirou_mega_gar_ totes_thalassaes_kratos_.  The last part of this extract, though often translated ‘command of the sea,’ or ’dominion of the sea,’ really has the wider meaning of sea-power, the ’power of the sea’ of the old English poet above quoted.  This wider meaning should be attached to certain passages in Herodotus,[13] which have been generally interpreted ‘commanding the sea,’ or by the mere titular and honorific ’having the dominion of the sea.’  One editor of Herodotus, Ch.  F. Baehr, did, however, see exactly what was meant, for, with reference to the allusion to Polycrates, he says, classemaximum_valuit_.  This is perhaps as exact a definition of sea-power as could be given in a sentence.

[Footnote 13:  Herodotus, iii. 122 in two places; v.83.]

It is, however, impossible to give a definition which would be at the same time succinct and satisfactory.  To say that ‘sea-power’ means the sum-total of the various elements that go to make up the naval strength of a state would be in reality to beg the question.  Mahan lays down the ’principal conditions affecting the sea-power of nations,’ but he does not attempt to give a concise definition of it.  Yet no one who has studied his works will find it difficult to understand what it indicates.

Our present task is to put readers in possession of the means of doing this.  The best, indeed—­as Mahan has made us see—­the only effective way of attaining this object is to treat the matter historically.  Whatever date we may agree to assign to the formation of the term itself, the idea—­as we have seen—­is as old as history.  It is not intended to give a condensed history of sea-power, but rather an analysis of the idea and what it contains, illustrating this analysis with examples from history ancient and modern.  It is important to know that it is not something which originated in the middle of the seventeenth century, and having seriously affected