C. Julius Caesar, Gallic War

While these things are being transacted, one legion had been sent to forage, according to custom, and no suspicion of war had arisen as yet, and some of the people remained in the country parts, others went backward and forward to the camp, they who were on duty at the gates of the camp reported to Caesar that a greater dust than was usual was seen in that direction in which the legion had marched. Caesar, suspecting that which was [really the case],-that some new enterprise was undertaken by the barbarians, ordered the two cohorts which were on duty, to march into that quarter with him, and two other cohorts to relieve them on duty; the rest to be armed and follow him immediately. When he had advanced some little way from the camp, he saw that his men were overpowered by the enemy and scarcely able to stand their ground, and that, the legion being crowded together, weapons were being cast on them from all sides. For as all the corn was reaped in every part with the exception of one, the enemy, suspecting that our men would repair to that, had concealed themselves in the woods during the night. Then attacking them suddenly, scattered as they were, and when they had laid aside their arms, and were engaged in reaping, they killed a small number, threw the rest into confusion, and surrounded them with their cavalry and chariots.