But Themistocles cherished yet greater designs even for securing the naval supremacy. When the fleet of the Hellenes, after the departure of Xerxes, had put in at Pagasae and was wintering there, he made a harangue before the Athenians, in which he said that he had a certain scheme in mind which would be useful and salutary for them, but which could not be broached in public.
So the Athenians bade him impart it to Aristides alone, and if he should approve of it, to put it into execution. Themistocles accordingly told Aristides that he purposed to burn the fleet of the Hellenes where it lay; but Aristides addressed the people, and said of the scheme which Themistocles purposed to carry out, that none could be either more advantageous or more iniquitous. The Athenians therefore ordered Themistocles to give it up.
At the Amphictyonic or Holy Alliance conventions, the Lacedaemonians introduced motions that all cities be excluded from the Alliance which had not taken part in fighting against the Mede. So Themistocles, fearing lest, if they should succeed in excluding the Thessalians and the Argives and the Thebans too from the convention, they would control the votes completely and carry through their own wishes, spoke in behalf of the protesting cities,
and changed the sentiments of the delegates by showing that only thirty-one cities had taken part in the war, and that the most of these were altogether small; it would be intolerable, then, if the rest of Hellas should be excluded and the convention be at the mercy of the two or three largest cities. It was for this reason particularly that he became obnoxious to the Lacedaemonians, and they therefore tried to advance Cimon in public favour, making him the political rival of Themistocles.