After these a space of four hundred yards (nearly a quarter of a mile) was left vacant; then marched, in a second continuous column, the remainder of the host.
On entering an enemy's country, or drawing near a hostile force in their own, certain alterations in these dispositions became necessary, and were speedily effected.

The baggage-train was withdrawn, and instead of moving before the army, followed at some little distance in the rear.
Horsemen were thrown out in front, to feel for the enemy and notify his arrival.

Sometimes, if the host was large, a division of the troops was made, and several _corps d'armee_ advanced against the foe simultaneously by distinct routes.

When this took place, the commander-in-chief was careful to accompany the central force, so as to find himself in his proper position if he was suddenly compelled to give battle.
Night movements were seldom attempted by the Persians.

They marched from sunrise to sunset, halting, probably, during the midday heat.