walls to its harbour of Nisaea, secured her from invasion on the side
of Peloponnesus. The great island of Euboea, with its rich pastures
and fruitful corn lands, had, since the Persian War, become an
Athenian estate, and was jealously guarded as one of her most valuable
possessions; and on the sea, from the eastern corner of the Euxine to
the strait of Gibraltar, there was none to dispute her sway.

But this rapid ascent was followed by no less speedy a fall, and one
act of indiscretion stripped the Athenians of all the advantages which
they had acquired on the mainland of Greece. In every city of Greece
there were always two parties, the wealthy and noble, called
oligarchs, and the demos, or commons; and according as Spartan or
Athenian influence was in the ascendant the balance of power in each
city wavered between the nobles and the people, the Athenians
favouring the Many, the Spartans the Few. Accordingly there was always
a party living in exile, and waiting for a turn of affairs which might
enable them to return to their city, and wrest the power from that
faction which had been the last to triumph. In the cities of Boeotia
the leaders of the oligarchs had been driven into banishment after the
battle of Oenophyta, and democracies were established under the
control of Athens. After nine years of banishment these exiles
returned, and the result was an oligarchical reaction in the chief
cities of Boeotia. A hastily equipped and ill-organised force was sent
out from Athens to put down the authors of the revolution, and in the
battle which followed, at Coronea, [Footnote: B.C. 447.] the Athenians
sustained a severe defeat, and a large number of their citizens were
taken prisoners by the Boeotians. To recover these prisoners the
Athenians consented to evacuate Boeotia, and by this surrender they
lost their hold on central Greece, as far as Thermopylae.