In early June of 480 B.C., a mighty Persian army crossed the Dardanelles strait on two pontoon bridges to continue a brutal advance into Greece. Led by the great king Xerxes, the troops were bound for Thermopylae, a narrow mountain pass named for the area’s hot sulfur springs (Thermopylae means “hot gates”). Seated on the east coast of Greece, between the Malian Gulf and the Kallidromo massif, some 85 miles (136 km) northwest of Athens, it is a rugged, craggy landscape of thick brush, thorny shrubs, and steep hillsides, where severe weather—torrential downpours and scorching heat—is the norm.
The dramatically inhospitable four-mile-long pass—the quickest and easiest way to advance from the plains of Thessaly into central Greece—would soon be the site of a legendary battle, an epic, three-day episode that has been memorialized in literature and history as an iconic example of heroic resistance against insurmountable odds.
Much of what is known about the Battle of Thermopylae (and about the Greco-Persian wars generally) comes from the Greek historian Herodotus, who wrote in the fifth century B.C. Other sources include the Sicilian historian Diodorus Siculus (whose first-century B.C. account was based in part on the earlier Greek historian Ephorus), the ancient Greeks Plutarch and Ctesias of Cnidus, the modern historian George Beardoe Grundy (who performed a topographical survey of the narrow pass at Thermopylae), and to a lesser extent, the Greek tragedian Aeschylus.