the results of similar efforts in our own day. It is this which
gives a living interest to even the very ancient history of
sea-power, and makes the study of it of great practical importance
to us now. We shall see, as we go on, how the phenomena connected
with it reappear with striking regularity in successive periods.
Looked at in this light, the great conflicts of former ages are
full of useful, indeed necessary, instruction.

[Footnote 14: Mommsen, _Hist._Rome_, English trans., i. p. 153.]

In the first and greatest of the contests waged by the nations
of the East against Europe--the Persian wars--sea-power was the
governing factor. Until Persia had expanded to the shores of the
Levant the European Greeks had little to fear from the ambition
of the great king. The conquest of Egypt by Cambyses had shown how
formidable that ambition could be when supported by an efficient
navy. With the aid of the naval forces of the Phoenician cities
the Persian invasion of Greece was rendered comparatively easy.
It was the naval contingents from Phoenicia which crushed the
Ionian revolt. The expedition of Mardonius, and still more that
of Datis and Artaphernes, had indicated the danger threatening
Greece when the master of a great army was likewise the master
of a great navy. Their defeat at Marathon was not likely to,
and as a matter of fact did not, discourage the Persians from
further attempts at aggression. As the advance of Cambyses into
Egypt had been flanked by a fleet, so also was that of Xerxes
into Greece. By the good fortune sometimes vouch-safed to a people
which, owing to its obstinate opposition to, or neglect of, a
wise policy, scarcely deserves it, there appeared at Athens an
influential citizen who understood all that was meant by the