Thermopylæ (i. e. "the hot gates"), a famous pass in N. Greece, the only traversable one leading southward into Thessaly, lies 25 m. N. of Delphi, and is flanked on one side by Mount Oeta, and on the other by the Maliac Gulf (now the Gulf of Zeitouni); for ever memorable as the scene of Leonidas' heroic attempt with his 300 Spartans to stem the advancing Persian hordes under Xerxes (480 B.C.); also of Greece's futile struggles against Brennus and the Gauls (279 B.C.), and Philip the Macedonian (207 B.C.)