In the interval between the battle of Miletus and the interview of Tissaphernes with the Spartan commissioners at Cnidus, some transactions had taken place, which were pregnant with very important changes, and gave a singular complexity to the affairs of the contending parties. Alcibiades, as we have seen, not only fought against his countrymen at Miletus, but exerted himself with great apparent earnestness and activity to deprive them of the fruits of their victory. Up to this moment there is no reason to doubt that he was seriously bent on serving the cause of the Peloponnesians, as that which was the sole foundation of his ambitious or vindictive hopes. But henceforth his conduct was entirely changed, and his views appear to have taken an opposite direction.

Though he had attracted great admiration at Sparta by his talents and address, and especially by the flexibility with which he adapted himself to the national character and habits, he does not seem to have gained any friends, and he made at least one implacable enemy, in king Agis. Thucydides only mentions the fact, without explaining the cause of his animosity. One quite adequate, and perfectly probable, is assigned by later writers, who relate that Agis suspected Alcibiades of having dishonoured his queen Timæa. The silence of Thucydides, on a point of this nature, cannot cast any doubt on the story, and since it is certain that Agis was convinced of his wife's infidelity, it would be an absurd stretch of incredulity to doubt that he believed Alcibiades to be her paramour.