Xenophon, Cyropaedia
Walter Miller, Ed.

[43] But how you ought to draw up an army in battle array, or how you ought to lead it by day or by night, by narrow ways or broad, over mountains or plains, or how you should pitch camp, or how station your sentinels by night or by day, or how you should advance against the enemy or retreat before them, or how you should lead past a hostile city, or how attack a fortification or withdraw from it, or how you should cross ravines or rivers, or how you should protect yourself against cavalry or spearmen or bowmen, and if the enemy should suddenly come in sight while you are leading on in column, how you should form and take your stand against them, and if they should come in sight from any other quarter than in front as you are marching in phalanx, how you should form and face them, or how any one might best find out the enemy's plans or how the enemy might be least likely to learn his—why should I tell you all these things? For what I, for my part, know, you have often heard; and if any one else had a reputation for understanding anything of that kind, you never neglected to get information from him, nor have you been uninstructed. I think, then, that you should turn this knowledge to account according to circumstances, as each item of it may appear serviceable to you.