History of the Peloponnesian War

These precautions the Athenians took with regard to the Potidaeans immediately after the seafight at Corcyra;

for the Corinthians were now openly at variance with them, and Perdiccas son of Alexander, king of the Macedonians, who had before been an ally and friend, had now become hostile.

And he had become hostile because the Athenians had made an alliance with his brother Philip and with Derdas, who were making common cause against himself.

Alarmed at this he kept sending envoys to Lacedaemon, trying to bring about a war between Athens and the Peloponnesians. He sought also to win over the Corinthians, with a view to the revolt of Potidaea;

and, furthermore, he made overtures to the Chalcidians of Thrace and the Bottiaeans to join in the revolt, thinking that if he had as allies these countries, which bordered on his own, it would be easier, in conjunction with them, to carry on the war.

But the Athenians became aware of these designs, and wishing to forestall the revolt of the cities, ordered the commanders of their fleet (since they happened to be sending against the country of Perdiccas thirty ships and a thousand hoplites under the command of Archestratus son of Lycomedes and four others) to take hostages of the Potidaeans and pull down their wall, and also to keep a watch upon the neighbouring towns and prevent them from revolting.