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.
So they set about preparing the fortifications, and in consequence of this Samos, which in any case would soon have been ready, was more quickly fortified. Not long afterward came the letter from Alcibiades, saying that the army was being betrayed by Phrynichus and that the enemy would soon attack.
But since Alcibiades was not regarded as a trustworthy man, but was believed, as he knew beforehand the plans of the enemy, to be actuated by personal enmity in attributing to Phrynichus a guilty knowledge of them, the accusation did Phrynichus no harm, but rather confirmed his statement by giving the same information.
After this Alcibiades continued to work on Tissaphernes and to urge him to be a friend to the Athenians. Now though Tissaphernes was afraid of the Peloponnesians, because they were there with a larger fleet than the Athenians, nevertheless he wanted to follow this advice if in any way he could do so, especially now that he had become aware of the disagreement that had arisen at Cnidos among the Peloponnesians[*](cf. 8.43.3.) about the treaty of Therimenes—for by this time the Peloponnesians were at Rhodes, so that the dispute had already taken place —in the course of which disagreement Lichas had verified the statement made before by Alcibiades, that it was the Lacedaemonian policy to liberate all the cities, declaring that it was intolerable to agree that the King should be master of all the cities over which he himself or his fathers had ever before held sway. Alcibiades, then, as one that contended for a great prize, was assiduously paying court to Tissaphernes.