Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

5. During the same winter, while both parties were as intent upon their preparations as if the¹ war were only just beginning, first among the Athenian subjects the Eubeans sent envoys to negotiate with Agis. Agis accepted their proposals, and summoned from Lacedaemon Alcamenes the son of Sthenelaidas, and Melanthus, that they might take the command in Euboea. They came, accompanied by three hundred of the Neodamodes. But while he was making ready to convey them across the strait, there arrived envoys from Lesbos, which was likewise anxious to revolt; [2] and as the Boeotians² were in their interest, Agis was persuaded to defer the expedition to Euboea while he prepared to assist the Lesbians. He appointed Alcamenes, who had been designed for Euboea, their governor; and he further promised them ten ships, the Boeotians promising ten more. All this was done without the authority of the Lacedaemonian government; [3] for Agis, while he was with his army at Decelea, had the right to send troops whithersoever he pleased, to raise levies, and to exact money. And at that particular time he might be said to have far more influence over the allies than the Lacedaemonians at home, for he had an army at his disposal, and might appear in formidable strength anywhere at any time.

While he was supporting the Lesbians, certain Chians and Erythraeans (who were also ready³ to revolt) had recourse, not to Agis, but to Lacedaemon; [4] they were accompanied by an envoy from Tissaphernes, whom King Darius the son of Artaxerxes had appointed to be military governor of the provinces on the coast of Asia. Tissaphernes too was inviting the assistance of the Lacedaemonians, and promised to maintain their troops; [5] for the King had quite lately been demanding of him the revenues due from the Hellenic cities in his province, which he had been prevented by the Athenians from collecting, and therefore still owed. He thought that if he could weaken the Athenians he would be more likely to get his tribute; he hoped also to make the Lacedaemonians allies of the King, and by their help either to slay or take alive, in accordance with the King's orders, Amorges the natural son of Pissuthnes, who had revolted in Caria.