History of the Peloponnesian War

and ten years after that the Barbarian came again with his great host against Hellas to enslave it. In the face of the great danger that threatened, the Lacedaemonians, because they were the most powerful, assumed the leadership of the Hellenes that joined in the war; and the Athenians, when the Persians came on, resolved to abandon their city, and packing up their goods embarked on their ships, and so became sailors. By a common effort the Barbarian was repelled; but not long afterwards the other Hellenes, both those who had revolted from the King and those who had joined the first confederacy against him, parted company and aligned themselves with either the Athenians or the Lacedaemonians; for these states had shown themselves the most powerful, the one strong by land and the other on the sea.

The defensive alliance lasted only a little while; then the Lacedaemonians and the Athenians quarrelled and, with their respective allies, made war upon one another, and any of the rest of the Hellenes, if they chanced to be at variance, from now on resorted to one or the other. So that from the Persian invasion continually, to this present war, making peace at one time, at another time fighting with each other or with their own revolted allies, these two states prepared themselves well in matters of war, and became more experienced, taking their training amid actual dangers.