As soon as the Aduatuci were informed of the disaster of the Nervii, they returned to their own country, abandoned their towns and forts, and retired, with all they possessed, into one _oppidum_, remarkably fortified by nature. Surrounded in every direction by precipitous rocks of great elevation, it was accessible only on one side by a gentle slope, at most 100 feet wide, defended by a fosse and double wall of great height, on which they placed enormous masses of rock and pointed beams. The mountain on which the citadel of Namur is situated[268] answers sufficiently to this description. (_See Plate 11._)
On the arrival of the army, they made at first frequent sorties, and engaged in battles on a small scale. Later, when the place was surrounded by a countervallation of twelve feet high in a circuit of 15,000 feet,[269] with numerous redoubts, they kept close in their _oppidum_. The Romans pushed forward their covered galleries, raised a terrace under shelter of these galleries, and constructed a tower of timber, intended to be pushed against the wall. At the sight of these preparations, the Aduatuci, who, like most of the Gauls, despised the Romans on account of their small stature, addressed the besiegers ironically from their walls, not understanding how a great machine, placed at a great distance, could be put in motion by men so diminutive. But when they saw this tower move and approach the walls, struck with a sight so strange and so new to them, they sent to implore peace, demanding, as the only condition, that they should be left in possession of their arms. Cæsar refused this condition, but declared that, if they surrendered before the ram had struck their wall, they should be placed, like the Nervii, under the protection of the Roman people, and preserved from all violence. The besieged thereupon threw such a quantity of arms into the fosses that they filled them almost to the height of the wall and the terrace; yet, as was afterwards discovered, they had retained about one-third. They threw open their gates, and that day remained quiet.
The Romans had occupied the town; towards evening, Cæsar ordered them to leave it, fearing the violences which the soldiers might commit on the inhabitants during the night. But these, believing that after the surrender of the place the posts of the countervallation would be guarded with less care, resume the arms they had concealed, furnish themselves with bucklers of bark of trees, or wicker, covered hastily with skins, and, at midnight, attack the part of the works which seems most easy of access. Fires, prepared by Cæsar, soon announce the attack. The soldiers rush to the spot from the nearest redoubts; and, though the enemies fight with the obstinacy of despair, the missiles thrown from the entrenchments and the towers disperse them, and they are driven back into the town with a loss of 4,000 men. Next day the gates were broken in without resistance, and, the town once taken, the inhabitants were sold publicly to the number of 53,000.[270]