History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
And at the end of the same summer[*](430 B.C.) Aristeus a Corinthian, three Lacedaemonian envoys, Aneristus, Nicolaus, and Pratodamus, also Timagoras of Tegea and Pollis of Argos, the last acting in a private capacity,[*](Because Argos was a neutral state: Thuc. 2.9.2.) set out for Asia to the King's court to see if they might persuade him to furnish money and join in the war. On their way they came first to Sitalces son of Teres in Thrace, their desire being to persuade him, if possible, to forsake the Athenian alliance and send a force to relieve Potidaea, where an Athenian army was conducting the siege; and also, in pursuance of their object, with his help to cross the Hellespont to Pharnaces[*](Then Satrap of Dascylium; Thuc. 1.129.1.) son of Pharnabazus, who was to escort them up the country to
the King. But two Athenian envoys, Learchus son of Callimachus and Ameiniades son of Philemon, who chanced to be visiting Sitalces, urged Sadocus son of Sitalces, who had been made an Athenian citizen,[*](Thuc. 2.29.5.) to deliver the men into their hands, that they might not cross over to the King and do such injury as might be to his