Meanwhile the Belgæ, after having concentrated their forces in the country of the Suessiones, to the north of the Aisne, had invaded the territory of the Remi. On their road, and at eight miles from the Roman camp (_see Plate 7_), was a town of the Remi called Bibrax (_Vieux-Laon_).[247] The Belgæ attacked it vigorously, and it was defended with difficulty all day. These peoples, like the Celts, attacked fortresses by surrounding them with a crowd of combatants, throwing from every side a great quantity of stones, to drive the defenders away from the walls; then, forming the tortoise, they advanced against the gates and sapped the walls. When night had put a stop to the attack, Iccius, who commanded in the town, sent information to Cæsar that he could hold out no longer, unless he received prompt succour. Towards midnight the latter sent him Numidians, Cretan archers, and Balearic slingers, who had the messengers of Iccius for their guides. This re-enforcement raised the courage of the besieged, and deprived the enemy of the hope of taking the town; and after remaining some time round Bibrax, laying waste the land and burning the hamlets and houses, they marched towards Cæsar, and halted at less than two miles from his camp. Their fires, kindled on the right bank of the Miette, indicated a front of more than 8,000 paces (twelve kilomètres). The great numbers of the enemy, and their high renown for bravery, led the proconsul to resolve to postpone the battle. If his legions had in his eyes an incontestible superiority, he wished, nevertheless, to ascertain what he could expect from his cavalry, which was composed of Gauls. For this purpose, and to try, at the same time, the courage of the Belgæ, he engaged them every day in cavalry combats in the undulated plain to the north of the camp. Once certain that his troops did not yield in valour to those of the enemy, he resolved to draw them into a general action. In front of the entrenchments was an extensive tract of ground, advantageous for ranging an army in order of battle. This commanding position was covered in front and on the left by the marshes of the Miette. The right only remained unsupported, and the Belgæ might have taken the Romans in flank in the space between the camp and the stream, or turned them by passing between the camp and the Aisne. To meet this danger, Cæsar made, on each of the two slopes of the hill, a fosse, perpendicular to the line of battle, about 400 paces (600 mètres) in length, the first reaching from the camp to the Miette, the second joining it to the Aisne. At the extremity of these fosses he established redoubts, in which were placed military machines.[248] [Sidenote: Battle on the Aisne.]