Herodotus

“ The barbarians, therefore, with Xerxes, advanced, and the Greeks with Leonidas, marching out as if for certain death, now advanced much farther than before into the wide part of the defile, for the fortification of the wall had protected them, and they on the preceding days, having taken up their position in the narrow part, fought there; but now engaging outside the narrows, great numbers of the barbarians fell; for the officers of the companies from behind, having scourges, flogged every man, constantly urging them forward ”

“ The Greeks at Thermopylæ, when the Persians came near the pass, being alarmed, consulted about a retreat; accordingly, it seemed best to the other Peloponnesians to retire to Peloponnesus, and guard the Isthmus; but Leonidas, perceiving the Phocians and Locrians were very indignant at this proposition, determined to stay there, and to despatch messengers to the cities, desiring them to come to their assistance, they being too few to repel the army of the Medes. ”

“ Demophilus, son of Diadromas, commanded them.
Xerxes, after he had poured out libations at sunrise, having waited a short time, began his attack about the time of full market, for he had been so instructed by Ephialtes; for the descent from the mountain is more direct and the distance much shorter than the circuit and ascent. ”

“ The number of his fighting men was over two millions and a half. His ships of war were twelve hundred and seven in number, and he had three thousand smaller vessels for carrying his land forces and supplies. At the narrow pass of Thermopylæ, in the northeast of Greece, this immense army was checked for a while by the heroic Leonidas and his three hundred Spartans, who, however, perished in their attempt to prevent the Persian's attack on Athens, which city was almost entirely destroyed by the invaders. The sea-fight of Salamis was won by the Greeks against enormous odds ”

“ I think that the servants who followed them, and with those on board the provision ships and other vessels that sailed with the fleet, were not fewer than the fighting men, but more numerous; but supposing them to be equal in number to the fighting men, they make up the former number of myriads. [2] Thus Xerxes, son of Darius, led five millions two hundred and eighty-three thousand two hundred and twenty men to Sepias and Thermopylæ! ”

“ In this place, then, the fleet of Xerxes was moored.
Fifteen of these ships happened to be driven out to sea some time after the rest, and somehow saw the ships of the Greeks at Artemisium. The barbarians thought that they were their own, and sailing on, fell among their enemies. They were commanded by Sandoces, son of Thaumasius, governor of Cyme, of Æolia. He, being one of the royal judges, had been formerly condemned by King Darius (who had detected him in the following offence) , to be crucified. ”

“ Accordingly, these situations appeared suitable for the Greeks; for they, having weighed everything beforehand, and considered that the barbarians would neither be able to use their numbers nor their cavalry, there resolved to await the invader of Greece. As soon as they were informed that the Persian was in Pieria, breaking up from the Isthmus some of them proceeded by land to Thermopylæ, and others by sea to Artemisium.
The Greeks, therefore, being appointed in two divisions, hastened to meet the enemy ”

“ Though the Lacedæmonians and Thespians behaved in this manner, yet Dieneces, a Spartan, is said to have been the bravest man. They relate that he made the following remark before they engaged with the Medes, having heard a Trachinian say that when the barbarians let fly their arrows they would obscure the sun by the multitude of their shafts, so great was their number ”

“ To this and the former number I add those that were on the penteconters [1] supposing eighty men on the average to be on board of each. Three thousand of these vessels were assembled; therefore the men on board them must have been two hundred and forty thousand. ”