When Mardonius formerly held his camp in Boeotia, all the Greeks of those parts who were friendly to the Medes sent troops to join his army, and these troops accompanied him in his attack upon Athens. The Phocians alone abstained, and took no part in the invasion; for, though they had espoused the Median cause warmly, it was very much against their will, and only because they were compelled so to do. However, a few days after the arrival of the Persian army at Thebes, a thousand of their heavy-armed soldiers came up, under the command of Harmocydes, one of their most distinguished citizens. No sooner had these troops reached Thebes, than some horsemen came to them from Mardonius, with orders that they should take up a position upon the plain, away from the rest of the army. The Phocians did so, and forthwith the entire Persian cavalry drew nigh to them: whereupon there went a rumour through the whole of the Greek force encamped with the Medes, that Mardonius was about to destroy the Phocians with missiles. The same conviction ran through the Phocian troops themselves; and Harmocydes, their leader, addressed them thus with words of encouragement- "Phocians" said he, "'tis plain that these men have resolved beforehand to take our lives, because of the accusations of the Thessalians, as I imagine. Now, then, is the time for you all to show yourselves brave men. 'Tis better to die fighting and defending our lives, than tamely to allow them to slay us in this shameful fashion. Let them learn that they are barbarians, and that the men whose death they have plotted are Greeks!"Thus spake Harmocydes; and the Persian horse, having encircled the Phocians, charged towards them, as if about to deal out death, with bows bent, and arrows ready to be let fly; nay, here and there some did even discharge their weapons. But the Phocians stood firm, keeping close one to another, and serrying their ranks as much as possible: whereupon the horse suddenly wheeled round and rode off. I cannot say with certainty whether they came, at the prayer of the Thessalians, to destroy the Phocians, but seeing them prepared to stand on their defence, and fearing to suffer damage at their hands, on that account beat a retreat, having orders from Mardonius so to act; or whether his sole intent was to try the temper of the Phocians and see whether they had any courage or no. However this may have been, when the horsemen retired, Mardonius sent a herald to the Phocians, saying- "Fear not, Phocians- ye have shown yourselves valiant men- much unlike the report I had heard of you. Now therefore be forward in the coming war. Ye will not readily outdo either the king or myself in services." Thus ended the affair of the Phocians.
The Lacedaemonians, when they reached the Isthmus, pitched their camp there; and the other Peloponnesians who had embraced the good side, hearing or else seeing that they were upon the march, thought it not right to remain behind when the Spartans were going forth to the war. So the Peloponnesians went out in one body from the Isthmus, the victims being favourable for setting forth; and marched as far as Eleusis, where again they offered sacrifices, and, finding the omens still encouraging, advanced further. At Eleusis they were joined by the Athenians, who had come across from Salamis, and now accompanied the main army. On reaching Erythrae in Boeotia, they learnt that the barbarians were encamped upon the Asopus; wherefore they themselves, after considering how they should act, disposed their forces opposite to the enemy upon the slopes of Mount Cithaeron.
Mardonius, when he saw that the Greeks would not come down into the plain, sent all his cavalry, under Masistius (or Macistius, as the Greeks call him), to attack them where they were. Now Masistius was a man of much repute among the Persians, and rode a Nisaean charger with a golden bit, and otherwise magnificently caparisoned. So the horse advanced against the Greeks, and made attacks upon them in divisions, doing them great damage at each charge, and insulting them by calling them women.
It chanced that the Megarians were drawn up in the position most open to attack, and where the ground offered the best approach to the cavalry. Finding themselves therefore hard pressed by the assaults upon their ranks, they sent a herald to the Greek leaders, who came and said to them, "This is the message of the Megarians- We cannot, brothers-in-arms, continue to resist the Persian horse in that post which we have occupied from the first, if we are left without succours. Hitherto, although hard pressed, we have held out against them firmly and courageously. Now, however, if you do not send others to take our place, we warn you that we shall quit our post."Such were the words of the herald. Pausanias, when he heard them, inquired among his troops if there were any who would volunteer to take the post, and so relieve the Megarians. Of the rest none were willing to go, whereupon the Athenians offered themselves; and a body of picked men, three hundred in number, commanded by Olympiodorus, the son of Lampo, undertook the service.
Selecting, to accompany them, the whole body of archers, these men relieved the Megarians, and occupied a post which all the other Greeks collected at Erythrae had shrunk from holding. After the struggle had continued for a while, it came to an end on this wise. As the barbarians continued charging in divisions, the horse of Masistius, which was in front of the others, received an arrow in his flank, the pain of which caused him to rear and throw his rider.
