The Persians had thrust their shields into the ground to form a rough barrier between them and the Spartans, while they sent shower after shower of arrows upon the loiterers. The Spartans soon tore down the breastwork of shields, and with their swords in their hands advanced upon the enemy.
Mardonius did all he could to encourage his men, but they had no armour to protect them from the blows of the Spartans, and they were forced back toward the river, throwing into confusion those of their own army who were still advancing.
In the thick of the battle Mardonius rode on a white horse, surrounded by ten thousand chosen Persians. He was easily known by his white charger, and many were the spears that were aimed at him by the angry Spartans. At length one smote him so that he fell dead to the ground. 'Thus,' says Herodotus, 'Mardonius paid the recompence for the murder of Leonidas.'
No sooner was their leader slain than the Persians fled in utter confusion, all but forty thousand who were led off the field by one of the generals, and these marching north reached the Hellespont and crossed over to Asia in safety.
Those who fled from the field took refuge in their camp, where the Spartans attacked them. But the barricades were strong, and the camp was not taken until the Athenians had returned and joined in the assault.
As the Greeks swarmed into the camp they slaughtered the enemy without mercy. So severe was the defeat of Plataea that the Persians were utterly crushed.
The spoil in the camp was enormous. Gold and silver dishes were there in abundance, rich carpets too, and weapons inlaid with precious stones. Horses, camels, mules were captured in great numbers.
It is told that the great king had left his own magnificent war camp for Mardonius to use.
When Pausanias saw it 'all blazing with gold and silver
