detachments of the best armed troops would be required to
garrison the city itself, and man the various fortified posts in
the territory; so that it is impossible to reckon the fully
equipped force that marched from Athens to Marathon, when the
news of the Persian landing arrived, at higher than ten thousand
men. [The historians who lived long after the time of the
battle, such as Justin, Plutarch and others, give ten thousand as
the number of the Athenian army. Not much reliance could be
placed on their authority, if unsupported by other evidence; but
a calculation made from the number of the Athenian free
population remarkably confirms it. For the data of this, see
Boeck's "Public Economy of Athens," vol. i. p. 45. Some METOIKOI
probably served as Hoplites at Marathon, but the number of
resident aliens at Athens cannot have been large at this period.]

With one exception, the other Greeks held back from aiding them.
Sparta had promised assistance; but the Persians had landed on
the sixth day of the moon, and a religious scruple delayed the
march of Spartan troops till the moon should have reached its
full. From one quarter only, and that a most unexpected one, did
Athens receive aid at the moment of her great peril.

For some years before this time, the little state of Plataea in
Boeotia, being hard pressed by her powerful neighbour, Thebes,
had asked the protection of Athens, and had owed to an Athenian
army the rescue of her independence. Now when it was noised over
Greece that the Mede had come from the uttermost parts of the
earth to destroy Athens, the brave Plataeans, unsolicited,
marched with their whole force to assist in the defence, and to
share the fortunes of their benefactors. The general levy of the