History of the Peloponnesian War

And in the tenth year after it, the barbarians came again with the great armament against Greece to enslave it. And when great danger was impending, the Lacedaemonians took the lead of the confederate Greeks, as being the most powerful; and the Athenians, on the approach of the Medes, determined to leave their city, and having broken up their establishments, [*]( Or, having removed their furniture, the word meaning, just there verse of κατασκευάζομαι. Bloomfield connects it with ἐς τὰς ναῦς.) went on board their slips, and became a naval people. And having together repulsed the barbarian, no long time after, both those Greeks who had revolted from the king, and those who had joined in the war [against him], were divided between the Athenians and Lacedaemonians. For these states respectively appeared the most powerful; for the one was strong by land, and the other by sea.

And for a short time the confederacy held together; but afterwards the Lacedaemonians and Athenians, having quarrelled, waged war against each other with their allies: and of the rest of the Greeks, whoever in any quarter were at variance, now betook themselves to these. So that, from the Persian war all the time to this, making peace at one time, and at another war, either with each other or with their own revolting allies, they prepared themselves well in military matters, and became more experienced from going through their training in scenes of danger. [*]( Their field of exercise was not the parade, but the field of battle. —Arnold.)