24. Ancient Greece’s Greatest Traitor
Ephialtes of Trachis, or Ephialtes son of Eurydemos, was a member of the Greek Malian tribe, after whom the Malian Gulf in the northwestern Aegean is named. When King Xerxes of Perisa invaded Greece in the 5th century BC, Ephialtes betrayed the Greeks by showing the Persians a path that allowed them to bypass and surround a Spartan-led blocking force that had halted the invaders at Thermopylae.
The invasion came after decades of mounting tensions, spurred by Athens’ support during the reign of Persia’s King Darius I of a failed rebellion by his Ionian Greek subjects in Asia Minor. That led to a Persian punitive expedition against Athens, which was defeated at the Battle of Marathon in 490 BC. In 480 BC, Darius’ son and successor, King Xerxes, gathered forces for a massive campaign to conquer and subdue Greece once and for all.