History of the Peloponnesian War

Whilst they thus varied, word was brought that the Illyrians had betrayed Perdiccas and joined themselves with Arrhibaeus. So that now it was thought good to retire by them both, for fear of these who were a warlike people; but yet for the time when to march, there was nothing concluded, by reason of their variance. The next night, the Macedonians and multitude of barbarians (as it is usual with great armies to be terrified upon causes unknown) being suddenly affrighted, and supposing them to be many more in number than they were, and even now upon them, betook themselves to present flight and went home. And Perdiccas, who at first knew not of it, they constrained when he knew, before he had spoken with Brasidas (their camps being far asunder), to be gone also.

Brasidas betimes in the morning, when he understood that the Macedonians were gone away without him, and that the Illyrians and Arrhibaeans were coming upon him, putting his men of arms into a square form and receiving the multitude of his light-armed into the middle, intended to retire likewise. The youngest men of his soldiers he appointed to run out upon the enemy when they charged the army anywhere [with shot];

and he himself, with three hundred chosen men marching in the rear, intended, as he retired, to sustain the foremost of the enemy, fighting if they came close up.

But before the enemy approached, he encouraged his soldiers, as the shortness of time gave him leave, with words to this effect: