C. Julius Caesar, Gallic War

Caesar, having disembarked his army and chosen a convenient place for the camp, when he discovered from the prisoners in what part the forces of the enemy had lodged themselves, having left ten cohorts and 300 horse at the sea, to be a guard to the ships, hastens to the enemy, at the third watch, fearing the less for the ships, for this reason because he was leaving them fastened at anchor upon an even and open shore; and he placed Q. Atrius over the guard of the ships. He himself, having advanced by night about twelve miles, espied the forces of the enemy. They, advancing to the river with their cavalry and chariots from the higher ground, began to annoy our men and give battle. Being repulsed by our cavalry, they concealed themselves in woods, as they had secured a place admirably fortified by nature and by art, which, as it seemed, they had before prepared on account of a civil war; for all entrances to it were shut up by a great number of felled trees. They themselves rushed out of the woods to fight here and there, and prevented our men from entering their fortifications. But the soldiers of the seventh legion, having formed a testudo and thrown up a rampart against the fortification, took the place and drove them out of the woods, receiving only a few wounds. But Caesar forbade his men to pursue them in their flight any great distance; both because he was ignorant of the nature of the ground, and because, as a great part of the day was spent, he wished time to be left for the fortification of the camp.