It is a question whether the idea of the balance of power be owing entirely to modern policy, or whether the phrase only has been invented in these latter ages. It is certain that Xenophon, in his institution of Cyrus, represents the combination of the Asiatic powers to have arisen from a jealousy of the increasing force of the Medes and Persians; and though that elegant composition should be supposed altogether a romance, this sentiment, ascribed by the author to the Eastern princes, is at least a proof of the prevailing notions of ancient times.
In all the politics of Greece the anxiety with regard to the balance of power is most apparent, and is expressly pointed out to us even by the ancient historians. Thucydides represents the league which was formed against Athens, and which produced the Peloponnesian war, as entirely owing to this principle. And after the decline of Athens, when the Thebans and Lacedemonians disputed for sovereignty, we find that the Athenians (as well as many other republics) threw themselves always into the lighter scale, and endeavoured to preserve the balance. They supported Thebes against Sparta, till the great victory gained by Epaminondas at Leuctra, after which they immediately went over to the conquered, from generosity as they pretended, but in reality from their jealousy of the conquerors.
Whoever will read Demosthenes’ oration for the Megalopolitans may see the utmost refinements on this principle which ever entered into the head of a Venetian or English speculatist; and upon the first rise of the Macedonian power, this orator immediately discovered the danger, sounded the alarm through all Greece, and at last assembled that