Gallic War

The horse and charioteers of the enemy contended vigorously in a skirmish with our cavalry on the march; yet so that our men were conquerors in all parts, and drove them to their woods and hills; but, having slain a great many, they pursued too eagerly, and lost some of their men. But the enemy, after some time had elapsed, when our men were off their guard, and occupied in the fortification of the camp, rushed out of the woods, and making an attack upon those who were placed on duty before the camp, fought in a determined manner; and two cohorts being sent by Caesar to their relief, and these severally the first of two legions, when these had taken up their position at a very small distance from each other, as our men were disconcerted by the unusual mode of battle, the enemy broke through the middle of them most courageously, and retreated thence in safety. That day, Q. Laberius Durus, a tribune of the soldiers, was slain. The enemy, since more cohorts were sent against them, were repulsed.

In the whole of this method of fighting since the engagement took place under the eyes of all and before the camp, it was perceived that our men, on account of the weight of their arms, inasmuch as they could neither pursue [the enemy when] retreating, nor dare quit their standards, were little suited to this kind of enemy; that the horse also fought with great danger, because they [the Britons] generally retreated even designedly, and, when they had drawn off our men a short distance from the legions, leaped from their chariots and fought on foot in unequal [and to them advantageous] battle. But the system of cavalry engagement is wont to produce equal danger, and indeed the same, both to those who retreat and to those who pursue. To this was added, that they never fought in close order, but in small parties and at great distances, and had detachments placed [in different parts], and then the one relieved the other, and the vigorous and fresh succeeded the wearied.

The following day the enemy halted on the hills, a distance from our camp, and presented themselves in small parties, and began to challenge our horse to battle with less spirit than the day before. But at noon, when Caesar had sent three legions, and all the cavalry, with C. Trebonius, the lieutenant, for the purpose of foraging, they flew upon the foragers suddenly from all quarters, so that they did not keep off [even] from the standards and the legions. Our men making an attack on them vigorously, repulsed them; nor did they cease to pursue them until the horse, relying on relief, as they saw the legions behind them, drove the enemy precipitately before them, and slaying a great number of them, did not give them the opportunity either of rallying, or halting, or leaping from their chariots. Immediately after this retreat, the auxiliaries who had assembled from all sides, departed; nor after that time did the enemy ever engage with us in very large numbers.

Caesar, discovering their design, leads his army into the territories of Cassivellaunus to the river Thames; which river can be forded in one place only and that with difficulty. When he had arrived there, he perceives that numerous forces of the enemy were marshaled on the other bank of the river; the bank also was defended by sharp stakes fixed in front, and stakes of the same kind fixed under the water were covered by the river. These things being discovered from [some] prisoners and deserters, Caesar, sending forward the cavalry, ordered the legions to follow them immediately. But the soldiers advanced with such speed and such ardor, though they stood above the water by their heads only, that the enemy could not sustain the attack of the legions and of the horse, and quitted the banks, and committed themselves to flight.