Ephialtes
（Ἐφιάλτης).
1.
One of the Aloadae ( Il. v. 385). See Aloeus.
2.
A Malian, who in B.C. 480, when Leonidas was defending the pass of Thermopylae, guided a body of Persians over the mountain path, and thus enabled them to fall on the rear of the Greeks.
3.
An Athenian statesman, a friend and partisan of Pericles, whom he assisted in carrying his political measures. He was instrumental in abridging the powers of the Areopagus—a measure assailed by Aeschylus in his Eumenides. Ephialtes thus made himself so obnoxious to the aristocratic party that his enemies had him assassinated, probably in the year B.C. 456.