XVI.--After he had made three days' march through their territories, he discovered from some prisoners, that the river Sambre was not more than ten miles from his camp: that all the Nervii had stationed themselves on the other side of that river, and together with the Atrebates and the Veromandui, their neighbours, were there awaiting the arrival of the Romans; for they had persuaded both these nations to try the same fortune of war [as themselves]: that the forces of the Aduatuci were also expected by them, and were on their march; that they had put their women, and those who through age appeared useless for war, in a place to which there was no approach for an army, on account of the marshes. XVII.--Having learnt these things, he sends forward scouts and centurions to choose a convenient place for the camp. And as a great many of the surrounding Belgae and other Gauls, following Caesar, marched with him; some of these, as was afterwards learnt from the prisoners, having accurately observed, during those days, the army's method of marching, went by night to the Nervii, and informed them that a great number of baggage-trains passed between the several legions, and that there would be no difficulty, when the first legion had come into the camp, and the other legions were at a great distance, to attack that legion while under baggage, which being routed, and the baggage-train seized, it would come to pass that the other legions would not dare to stand their ground. It added weight also to the advice of those who reported that circumstance, that the Nervii, from early times, because they were weak in cavalry (for not even at this time do they attend to it, but accomplish by their infantry whatever they can), in order that they might the more easily obstruct the cavalry of their neighbours if they came upon them for the purpose of plundering, having cut young trees, and bent them, by means of their numerous branches [extending] on to the sides, and the quick-briars and thorns springing up between them, had made these hedges present a fortification like a wall, through which it was not only impossible to enter, but even to penetrate with the eye. Since [therefore] the march of our army would be obstructed by these things, the Nervii thought that the advice ought not to be neglected by them. XVIII.--The nature of the ground which our men had chosen for the camp was this: A hill, declining evenly from the top, extended to the river Sambre, which we have mentioned above: from this river there arose a [second] hill of like ascent, on the other side and opposite to the former, and open from about 200 paces at the lowest part; but in the upper part, woody, (so much so) that it was not easy to see through it into the interior. Within those woods the enemy kept themselves in concealment; a few troops of horse-soldiers appeared on the open ground, along the river. The depth of the river was about three feet.