History of the Peloponnesian War

He accordingly had them seized, as they were travelling through Thrace to the vessel in which they were to cross the Hellespont, by a party whom he had sent on with Learchus and Ameiniades, and gave orders for their delivery to the Athenian ambassadors, by whom they were brought to Athens.

On their arrival, the Athenians, afraid that Aristeus, who had been notably the prime mover in the previous affairs of Potidaea and their Thracian possessions, might live to do them still more mischief if he escaped, slew them all the same day, without giving them a trial or hearing the defence which they wished to offer, and cast their bodies into a pit; thinking themselves justified in using in retaliation the same mode of warfare which the Lacedaemonians had begun, when they slew and cast into pits all the Athenian and allied traders whom they caught on board the merchantmen round Peloponnese. Indeed, at the outset of the war, the Lacedaemonians butchered as enemies all whom they took on the sea, whether allies of Athens or neutrals.