III. Although Cæsar had succeeded in uniting his troops, and in placing himself at their head, he found it still difficult to fix upon a determined plan. If he opened the campaign too early, the army might run short of provisions through the difficulty of transport. If, on the other hand, during the rest of the winter,[466] his army, remaining inactive, allowed Vercingetorix to take Gorgobina, a place tributary to the Ædui, the example might discourage his allies and lead to the defection of the whole of Gaul. Rather than undergo such an affront, he resolved to brave all obstacles. He engaged the Ædui, therefore, to furnish provisions, announced his speedy arrival to the Boii, recommended them to remain faithful, and to offer an energetic resistance; and then, leaving at Agedincum two legions and the baggage of the whole army, he marched with the eight others towards the territory of the Boii. On the second day[467] he arrived at Vellaunodunum (_Triguères_), a town of the Senones, and prepared to lay siege to it, in order to protect his rear and secure his supply of provisions. (_See Plate 19._) The countervallation was finished in two days. On the third, the town offered to surrender: the capitulation was only accepted on condition of delivering up the arms, the beasts of burden, and 600 hostages. Cæsar left C. Trebonius, his lieutenant, to see the convention executed, and marched in haste towards Genabum (_Gien_), a town of the Carnutes.[468] He arrived there in two days, and sufficiently early to surprise the inhabitants, who, thinking that the siege of Vellaunodunum would last longer, had not yet assembled sufficient troops for the defence of the place. The Roman army took its position before the _oppidum_; but the approach of night made it necessary to postpone the attack until the following morning. However, as Genabum had a bridge on the Loire adjoining to the town, Cæsar kept two legions under arms to watch it, in the fear that the besieged might escape during the night. And, in fact, towards midnight they silently issued from Genabum and began to pass the river. Cæsar, informed by his scouts, set fire to the gates, introduced the legions he had kept in reserve, and took possession of the place. The fugitives, who were closely crowded together at the issues of the town, and at the entrance of the bridge, which were too narrow to allow them to pass, fell nearly all into the hands of the Romans. Genabum was plundered and burnt, and the spoil abandoned to the soldiers. Then the army passed the Loire, arrived on the territory of the Bituriges, and continued its march.