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
Battle of Thermopylae he selected only Spartans with living sons. The Spartan force was reinforced "en route" to Thermopylae by contingents from various cities and numbered more than 7,000 by the time it arrived at the pass. Leonidas chose to camp at, and defend, the "middle gate", the narrowest part of the pass of Thermopylae, where the Phocians had built a defensive wall some time before. News also reached Leonidas, from the nearby city of Trachis, that there was a mountain track that could be used to outflank the pass of Thermopylae. Leonidas stationed 1,000 Phocians on the heights to prevent such a