XIV.--After spending several days in the same camp, the guards of the Bellovaci, learning that Caius Trebonius was advancing nearer with his legions, and fearing a siege like that of Alesia, send off by night all who were disabled by age or infirmity, or unarmed, and along with them their whole baggage. Whilst they are preparing their disorderly and confused troop for march (for the Gauls are always attended by a vast multitude of waggons, even when they have very light baggage), being overtaken by daylight, they drew their forces out before their camp, to prevent the Romans attempting a pursuit before the line of their baggage had advanced to a considerable distance. But Caesar did not think it prudent to attack them when standing on their defence, with such a steep hill in their favour, nor keep his legions at such a distance that they could quit their post without danger: but, perceiving that his camp was divided from the enemy's by a deep morass, so difficult to cross that he could not pursue with expedition, and that the hill beyond the morass, which extended almost to the enemy's camp, was separated from it only by a small valley, he laid a bridge over the morass and led his army across, and soon reached the plain on the top of the hill, which was fortified on either side by a steep ascent. Having there drawn up his army in order of battle, he marched to the furthest hill, from which he could, with his engines, shower darts upon the thickest of the enemy. XV.--The Gauls, confiding in the natural strength of their position, though they would not decline an engagement if the Romans attempted to ascend the hill, yet dared not divide their forces into small parties, lest they should be thrown into disorder by being dispersed, and therefore remained in order of battle. Caesar, perceiving that they persisted in their resolution, kept twenty cohorts in battle array, and, measuring out ground there for a camp, ordered it to be fortified. Having completed his works, he drew up his legions before the rampart and stationed the cavalry in certain positions, with their horses bridled. When the Bellovaci saw the Romans prepared to pursue them, and that they could not wait the whole night, or continue longer in the same place without provisions, they formed the following plan to secure a retreat. They handed to one another the bundles of straw and sticks on which they sat (for it is the custom of the Gauls to sit when drawn up in order of battle, as has been asserted in former commentaries), of which they had great plenty in their camp, and piled them in the front of their line; and at the close of the day, on a certain signal, set them all on fire at one and the same time. The continued blaze soon screened all their forces from the sight of the Romans, which no sooner happened than the barbarians fled with the greatest precipitation.