History of the Peloponnesian War
Thucydides
Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.
When he reached the frontier and was just going to be dismissed, he departed with these words: ‘This day will be the beginning of great misfortunes to the Hellenes.’
As soon as he arrived at the camp, and Archidamus learnt that the Athenians had still no thoughts of submitting, he at length began his march, and advanced with his army into their territory.
Meanwhile the Boeotians, sending their contingent and cavalry to join the Peloponnesian expedition, went to Plataea with the remainder and laid waste the country.
While the Peloponnesians were still mustering at the Isthmus, or on the march before they invaded Attica, Pericles, son of 13anthippus, one of the ten generals of the Athenians, finding that the invasion was to take place, conceived the idea that Archidamus, who happened to be his friend, might possibly pass by his estate without ravaging it. This he might do, either from a personal wish to oblige him, or acting under instructions from Lacedaemon for the purpose of creating a prejudice against him, as had been before attempted in the demand for the expulsion of the accursed family. He accordingly took the precaution of announcing to the Athenians in the assembly that, although Archidamus was his friend, yet this friendship should not extend to the detriment of the state, and that in case the enemy should make his houses and lands an exception to the rest and not pillage them, he at once gave them up to be public property, so that they should not bring him into suspicion.
He also gave the citizens some advice on their present affairs in the same strain as before. They were to prepare for the war, and to carry in their property from the country. They were not to go out to battle, but to come into the city and guard it, and get ready their fleet, in which their real strength lay. They were also to keep a tight rein on their allies—the strength of Athens being derived from the money brought in by their payments, and success in war depending principally upon conduct and capital.