C. Julius Caesar, Gallic War

About the same time Caesar, although the summer was nearly past, yet, since, all Gaul being reduced, the Morini and the Menapii alone remained in arms, and had never sent embassadors to him [to make a treaty] of peace, speedily led his army thither, thinking that that war might soon be terminated. They resolved to conduct the war on a very different method from the rest of the Gauls; for as they perceived that the greatest nations [of Gaul] who had engaged in war, had been routed and overcome, and as they possessed continuous ranges of forests and morasses, they removed themselves and all their property thither. When Caesar had arrived at the opening of these forests, and had began to fortify his camp, and no enemy was in the mean time seen, while our men were dispersed on their respective duties, they suddenly rushed out from all parts of the forest, and made an attack on our men. The latter quickly took up arms and drove them back again to their forests; and having killed a great many, lost a few of their own men while pursuing them too far through those intricate places.