Its prestige was seriously undermined by the conduct of individual members, whose corrupt use of power was exposed and punished by Ephialtes, the democratic leader.
Furthermore it is not till 457 that even a Zeugite archon is known, according to the Constitution of Athens (c. 26), which dates the change as five years after the death of Ephialtes and does not connect it with Aristides.
To Ephialtes likewise we must ascribe the renunciation of the Spartan alliance and the new league with Argos and Thessaly (461).
Though Themistocles soon lost his influence, his party eventually found a new leader in Ephialtes and after the failure of Cimon's foreign policy (see Cimon) triumphed over the conservatives.
Not long after, however, when Ephialtes fell by the dagger, Pericles undoubtedly assumed the leading position in the state.