Herodotus provides the primary surviving historical account of the Battle of Thermopylae. His narrative appears in Book VII of the Histories, which describes the Greek defence of the pass, Leonidas’ decisions, the Persian outflanking route, and the final destruction of the rearguard.
Herodotus was a Greek historian from Halicarnassus who wrote in the fifth century BC, within decades of the 480 BC invasion. His account includes speeches, reported conversations, troop numbers, and stories such as the response “Molon labe.” Some details are debated, especially the enormous figures given for the Persian army, but his work remains the central literary source for reconstructing the battle.
Other ancient writers also discuss Thermopylae. Diodorus Siculus gives a later account, while Plutarch and Ctesias preserve additional traditions. Simonides’ epitaphs and archaeological discoveries add useful evidence, but none provides a surviving narrative as full and influential as Herodotus’ account.