Battle of Thermopylae aware that his force was being outflanked, dismissed the bulk of the Greek army and remained to guard their retreat with 300 Spartans and 700 Thespians, fighting to the death. Others also reportedly remained, including up to 900 helots and 400 Thebans; these Thebans mostly reportedly surrendered. Themistocles was in command of the Greek Navy at Artemisium when he received news that the Persians had taken the pass at Thermopylae. Since the Greek strategy required both Thermopylae and Artemisium to be held, given their losses, it was decided to withdraw to Salamis. The Persians overran Boeotia and then captured the
Hydarnes II Hydarnes II Hydarnes II (, Old Persian: Vidarna), son of Hydarnes, was a Persian commander of the Achaemenid Empire in the 5th century BC. His father was one of the seven conspirators against Gaumata. During the reign of Xerxes I, Hydarnes was one of the commanders for the Second Persian invasion of Greece in 480 BC. He was appointed as the leader of the 10,000-man contingent of "Immortals", while his brother Sisamnes commanded the levy of the Aryans. On the first day of the Battle of Thermopylae, Hydarnes led the Immortals against the phalanx of Spartans under Leonidas I, but