He was regarded as safer there than he would have been on either wing; and it was seen that, from such a position, his orders would be most rapidly conveyed to all parts of the battlefield.

It was not, however, thought to be honorable that he should keep aloof from the fight, or avoid risking his own person.

On the contrary, he was expected to take an active part in the combat; and therefore, though his place was not exactly in the very foremost ranks, it was towards the front, and the result followed that he was often exposed to imminent danger.

The consequences of this arrangement were frequently disastrous in the extreme, the death or flight of the commander producing universal panic, stopping the further issue of any general order, and thus paralyzing the whole army.
The numbers of a Persian army, though no doubt exaggerated by the Greeks, must have been very great, amounting, probably, on occasions, to more than a million of combatants.

Troops were drawn from the entire empire, and were marshalled in the field according to nations, each tribe accoutred in its own fashion.