Ephialtes was the son of Eurydemus of Malis. He betrayed his homeland, in hope of receiving some kind of reward from the Persians, by showing the Persian forces a path around the allied Greek position at the pass of Thermopylae, which helped them win the Battle of Thermopylae in 480 BCE
After the betrayal of Ephialtes, the name "Ephialtes" received a lasting stigma; it came to mean "nightmare" in the Greek language and to symbolize the archetypal traitor in Greek culture.
Ephialtes of Trachis
Ephialtes was the son of Eurydemus of Malis. He betrayed his homeland, in hope of receiving some kind of reward from the Persians, by showing the Persian forces a path around the allied Greek position at the pass of Thermopylae, which helped them win the Battle of Thermopylae in 480 BCE
After the betrayal of Ephialtes, the name "Ephialtes" received a lasting stigma; it came to mean "nightmare" in the Greek language and to symbolize the archetypal traitor in Greek culture.