The imposing position of Caesar in Gaul depended essentially on the halo of victory that surrounded him; and this began to grow pale. The conflicts around Avaricum, Caesar's vain attempts to compel the enemy to fight, the resolute defence of the city and its almost accidental capture by storm bore a stamp different from that of the earlier Celtic wars, and had strengthened rather than impaired the confidence of the Celts in themselves and their leader.
Moreover, the new system of warfare - the making head against the enemy in intrenched camps under the protection of fortresses - had completely approved itself at Lutetia as well as at Gergovia. Lastly, this defeat, the first which Caesar in person had suffered from the Celts crowned their success, and it accordingly gave as it were the signal for a second outbreak of the insurrection.
The Haedui now broke formally with Caesar and entered into union with Vercingetorix. Their contingent, which was still with Caesar's army, not only deserted from it, but also took occasion to carry off the depots of the army of Caesar at Noviodunum on the Loire, whereby the chests and magazines, a number of remount-horses, and all the hostages furnished to Caesar, fell into the hands of the insurgents. It was of at least equal importance, that on this news the Belgae, who had hitherto kept aloof from the whole movement, began to bestir themselves. The powerful canton of the Bellovaci rose with the view of attacking in the rear the corps of Labienus, while it confronted at Lutetia the levy of the surrounding cantons of central Gaul.
Everywhere else too men were taking to arms; the strength of patriotic enthusiasm carried along with it even the most decided and most favoured partisans of Rome, such as Commius king of the Atrebates, who on account of his faithful services had received from the Romans important privileges for his community and the hegemony over the Morini. The threads of the insurrection ramified even into the old Roman province: they cherished the hope, perhaps not without ground, of inducing the Allobroges themselves to take arms against the Romans. With the single exception of the Remi and of the districts - dependent immediately on the Remi - of the Suessiones, Leuci, and Lingones, whose peculiar isolation was not affected even amidst this general enthusiasm, the whole Celtic nation from the Pyrenees to the Rhine was now in reality, for the first and for the last time, in arms for its freedom and nationality; whereas, singularly enough, the whole German communities, who in the former struggles had held the foremost rank, kept aloof. In fact, the Treveri, and as it would seem the Menapii also, were prevented by their feuds with the Germans from taking an active part in the national war.
It was a grave and decisive moment, when after the retreat from Gergovia and the loss of Noviodunum a council of war was held in Caesar's headquarters regarding the measures now to be adopted. Various voices expressed themselves in favour of a retreat over the Cevennes into the old Roman province, which now lay open on all sides to the insurrection and certainly was in urgent need of the legions that had been sent from Rome primarily for its protection. But Caesar rejected this timid strategy suggested not by the position of affairs, but by government-instructions and fear of responsibility. He contented himself with calling the general levy of the Romans settled in the province to arms, and having the frontiers guarded by that levy to the best of its ability. On the other hand he himself set out in the opposite direction and advanced by forced marches to Agedincum, to which he ordered Labienus to retreat in all haste. The Celts naturally endeavoured to prevent the junction of the two Roman armies. Labienus might by crossing the Marne and marching down the right bank of the Seine have reached Agedincum, where he had left his reserve and his baggage; but he preferred not to allow the Celts again to behold the retreat of Roman troops. He therefore instead of crossing the Marne crossed the Seine under the eyes of the deluded enemy, and on its left bank fought a battle with the hostile forces, in which he conquered, and among many others the Celtic general himself, the old Camulogenus, was left on the field. Nor were the insurgents more successful in detaining Caesar on the Loire; Caesar gave them no time to assemble larger masses there, and without difficulty dispersed the militia of the Haedui, which alone he found at that point
Thus the junction of the two divisions of the army was happily accomplished. The insurgents meanwhile had consulted as to the farthe conduct of the war at Bibracte (Autun) the capital of the Haeduil the soul of these consultations was again Vercingetorix, to whom the nation was enthusiastically attached after the victory of Gergovia. Particular interests were not, it is true, even now silent; the Haedui still in this death-struggle of the nation asserted their claims to the hegemony, and made a proposal in the national assembly to substitute a leader of their own for Vercingetorix. But the national representatives had not merely declined this and confirmed Vercingetorix in the supreme command, but had also adopted his plan of war without alteration. It was substantially the same as that on which he had operated at Avaricum and at Gergovia. As the base of the new position there was selected the strong city of the Mandubii, Alesia (Alise Sainte Reine near Semur in the department Cote d'Or)[49] and another entrenched camp was constructed under its walls. Immense stores were here accumulated, and the army was ordered thither from Gergovia, having its cavalry raised by resolution of the national assembly to 15,000 horse. Caesar with the whole strength of his army after it was reunited at Agedincum took the direction of Besancon, with the view of now approaching the alarmed province and protecting it from an invasion, for in fact bands of insurgents had already shown themselves in the territory of the Helvii on the south slope of the Cevennes. Alesia lay almost on his way; the cavalry of the Celts, the only arm with which Vercingetorix chose to operate, attacked him on the route, but to the surprise of all was worsted by the new German squadrons of Caesar and the Roman infantry drawn up in support of them.
Vercingetorix hastened the more to shut himself up in Alesia; and if Caesar was not disposed altogether to renounce the offensive, no course was left to him but for the third time in this campaign to proceed by way of attack with a far weaker force against an army encamped under a well-garrisoned and well-provisioned fortress and supplied with immense masses of cavalry. But, while the Celts had hitherto been opposed by only a part of the Roman legions, the whole forces of Caesar were united in the lines round Alesia, and Vercingetorix did not succeed, as he had succeeded at Avaricum and Gergovia, in placing his infantry under the protection of the walls of the fortress and keeping his external communications open for his own benefit by his cavalry, while he interrupted those of the enemy. The Celtic cavalry, already discouraged by that defeat inflicted on them by their lightly esteemed opponents, was beaten by Caesar's German horse in every encounter. The line of circumvallation of the besiegers extending about nine miles invested the whole town, including the camp attached to it.
49. The question so much discussed of late, whether Alesia is not rather to be identified with Alaise (25 kilometres to the south of Besancon, dep. Doubs), has been rightly answered in the negative by all judicious inquirers.