C. Julius Caesar, Gallic War

At day-break, when the summit of the mountain was in the possession of Titus Labienus, and he himself was not further off than a mile and half from the enemy's camp, nor, as he afterward ascertained from the captives, had either his arrival or that of Labienus been discovered; Considius, with his horse at full gallop, comes up to him says that the mountain which he [Caesar] wished should be seized by Labienus, is in possession of the enemy; that he has discovered this by the Gallic arms and ensigns. Caesar leads off his forces to the next hill: [and] draws them up in battle-order. Labienus, as he had been ordered by Caesar not to come to an engagement unless [Caesar's] own forces were seen near the enemy's camp, that the attack upon the enemy might be made on every side at the same time, was, after having taken possession of the mountain, waiting for our men, and refraining from battle. When, at length, the day was far advanced, Caesar learned through spies, that the mountain was in possession of his own men, and that the Helvetii had moved their camp, and that Considius, struck with fear, had reported to him, as seen, that which he had not seen. On that day he follows the enemy at his usual distance, and pitches his camp three miles from theirs.