Arrival of Cæsar at Decetia, and March towards Auvergne.

V. The winter was drawing to a close, and the season was propitious for the continuation of military operations. As Cæsar prepared to march against the enemy, either in order to draw him from the woods and marshes, or to shut him up in them, the principes of the Ædui came to request him to put an end to dissensions among them which threatened to degenerate into civil war. “The situation was most critical. In fact, according to ancient customs, the supreme authority was only granted to a single magistrate, named for a year. At that moment, however, there were two, each claiming to have been legally elected. The first was Convictolitavis, a young man of illustrious birth; the second, Cotus, sprung from a very ancient family, powerful also by his personal influence, his alliances, and whose brother, Valetiacus, had the year before filled the same office. The country was in arms, the Senate divided like the people, each of the pretenders at the head of his clients. The authority of Cæsar alone could prevent civil war.”

The Roman general considered it essential to prevent troubles from arising in an important state, closely attached to the Republic, and where the weakest party would not fail to call in the aid of Vercingetorix. Consequently, notwithstanding the inconvenience of suspending the military operations and moving from the enemy, he resolved to repair to the Ædui, whose first magistrate, according to the laws, could not leave the territory. Having thus aimed at proving to them the respect which he entertained for their institutions, he arrived at Decetia (Decize, in the Nivernais), where he called before him the Senate and the two pretenders.[481] Nearly the whole nation came thither. Cæsar, having acquired the conviction that the nomination of Cotus was the result of an intrigue of the minority, obliged him to resign, and maintained Convictolitavis, who had been chosen by the priests, according to the legal forms and customs of the country.

After this decision, he engaged the Ædui to forget their quarrels, and to devote themselves entirely to the war; Gaul once subjected, he would recompense them for their sacrifices. He exacted from them all their cavalry and 10,000 infantry, intending to distribute them in such a manner as to ensure the regularity of the victualling department. He next divided his army into two bodies. Labienus, detached with two legions and part of the cavalry, had instructions to take at Sens the two other legions which Cæsar had left there, and to repair, at the head of those four legions, to the country of the Parisii, who had been drawn by Vercingetorix into the revolt.

On his part, Cæsar resolved, with the six other legions and the rest of the cavalry, to invade the country of the Arverni themselves, the focus of the insurrection. He started from Decetia, and directed his march upon Gergovia, the principal oppidum of that people.

After the capture of Avaricum, Vercingetorix, suspecting Cæsar’s ulterior designs, had moved towards the Allier, which the Romans were obliged to pass in order to reach Gergovia; and, on the news of their march, he had caused all the bridges to be destroyed.

Cæsar, having arrived on the banks of the Allier, towards Moulins (see Plate 19), followed its downward course, on the right bank. Vercingetorix, on his part, marched along the opposite bank. The two armies were within sight of each other, the camps nearly opposite, and the Gaulish scouts, who watched the left bank, prevented the Romans from establishing a bridge. The position of the latter was difficult, for the Allier, which is fordable in the autumn only, might delay their passage a long time.[482] In order to surmount this obstacle, Cæsar had recourse to a stratagem: he fixed his camp in a place covered with wood, opposite the remains of one of the bridges which Vercingetorix had caused to be destroyed (probably at Varennes). There he remained hidden the following day with two legions, and made the rest of the troops, as well as the baggage, proceed in the usual order. But, that they might present to the enemy the appearance of six legions, he had divided into six corps the forty cohorts or four legions which he sent forward.[483] They received the order to march as long as possible, in order to attract Vercingetorix, and, at the time Cæsar presumed that they had arrived at their camp, he caused the bridge to be rebuilt on the old piles, the lower part of which remained untouched. The work being soon completed, the legions which remained with him passed the river, and, after having chosen a favourable position, he recalled the mass of his army, which rejoined him during the night.[484] When Vercingetorix was informed of this manœuvre, fearing lest he should be compelled to fight against his will, he took the start and marched in great haste to occupy the oppidum of the Arverni.

From the place he occupied, which we believe to have been Varennes,[485] Cæsar reached Gergovia in five days; on the very day of his arrival, after a slight skirmish of cavalry, he reconnoitred the position of the town. As it was built on a very high mountain of difficult access, he considered it impossible to take it by assault; he therefore resolved to blockade it, and not to begin investing it until he had assured his provisions. (See Plate 21.)

Blockade of Gergovia.

VI. The oppidum of the Arverni was situated at a distance of six kilomètres to the south of Clermont-Ferrand, on the mountain which has preserved the name of Gergovia. Its summit, elevated about 740 mètres above the level of the sea, and 380 above the plain, forms a plateau of 1,500 mètres in length by more than 500 mètres in breadth. The northern and eastern slopes present such abrupt declivities that they defy the escalade. The southern slope presents a very different character: it may be compared to an immense staircase, the steps of which would be vast terraces with very little inclination, and a breadth which in some places extends to as much as 150 mètres.