Julius Caesar Gallic War 7.33

Although Caesar considered it ruinous to leave the war and the enemy, yet, being well aware what great evils generally arise from internal dissensions, lest a state so powerful and so closely connected with the Roman people, which he himself had always fostered and honored in every respect, should have recourse to violence and arms, and that the party which had less confidence in its own power should summon aid from Vercingetorix, he determined to anticipate this movement; and because, by the laws of the Aedui, it was not permitted those who held the supreme authority to leave the country, he determined to go in person to the Aedui, lest he should appear to infringe upon their government and laws, and summoned all the senate, and those between whom the dispute was, to meet him at Decetia. When almost all the state had assembled there, and he was informed that one brother had been declared magistrate by the other, when only a few persons were privately summoned for the purpose, at a different time and place from what he ought, whereas the laws not only forbade two belonging to one family to be elected magistrates while each was alive, but even deterred them from being in the senate, he compelled Cotus to resign his office; he ordered Convictolitanis, who had been elected by the priests, according to the usage of the state, in the presence of the magistrates, to hold the supreme authority.