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.