Ephialtes of Trachis

Ephialtes was a native of the Trachinian district near the hot springs that gave Thermopylae its name. Herodotus names him the son of Eurydemus, a local who knew the mountains and the traffic of the coastal road where caravans threaded between cliff and sea. He was no general, no magistrate—just a man from the shadowed edge of a pass about to become the hinge of history. In a war waged by kings and city-states, his knowledge of a goat-track through scrub pine and schist would matter more than a thousand splendid speeches.

During the second invasion of Greece in 480 BC, after two days of failed assaults against the Greek phalanx in the narrows, Xerxes sought another way through. By night Ephialtes went to the Persian camp and revealed the Anopaea path that curved behind Leonidas’ position. For pay or promised favor—motives the sources dispute—he led Hydarnes’ Immortals up through the dark, brushing past startled Phocian sentries who fell back to higher ground. At dawn, the Persians appeared above the pass, and the trap closed. Leonidas dismissed most allies, then fought to the death with 300 Spartans and 700 Thespians on Kolonos Hill. The breakthrough opened central Greece to Xerxes and forced the Greek fleet to withdraw from Artemisium to Salamis, where the strategic balance would shift later that year.

Ephialtes’ choice invited infamy. The Amphictyons and Spartans posted a bounty on him, and he fled north into Thessaly. Years later, he was killed at Anticyra by a man named Athenades in a private quarrel; some Greeks mistakenly credited the slaying to patriotic vengeance. Greek writers could not agree on his inner life—avarice, fear, resentment—but agreed on the deed’s scale. He had wagered small knowledge for large reward and discovered too late that some communities never forget.

His legacy is written in a single word: ephialtes, “nightmare,” a label ancient Greeks pinned to betrayal in their darkest stories. In the moral math of Thermopylae, Leonidas defined obedience to law; Ephialtes defined its negation. Yet even his treachery fits the timeline’s theme: in narrow places, where mountains meet the sea, the smallest turn—one man’s guidance through a thicketed path—can decide the fates of armies. Ephialtes reminds us that history’s pivots are not always held by heroes; sometimes they are sold by those who know the back way in.