C. Julius Caesar, Gallic War

Having learned this fact, Caesar, because he had conferred so much honor upon the Aeduan state, determined that Dumnorix should be restrained and deterred by whatever means he could; and that, because he perceived his insane designs to be proceeding further and further, care should be taken lest he might be able to injure him and the commonwealth. Therefore, having stayed about twenty-five days in that place, because the north wind, which usually blows a great part of every season, prevented the voyage, he exerted himself to keep Dumnorix in his allegiance [and] nevertheless learn all his measures: having at length met with favorable weather, he orders the foot soldiers and the horse to embark in the ships. But, while the minds of all were occupied, Dumnorix began to take his departure from the camp homeward with the cavalry of the Aedui, Caesar being ignorant of it. Caesar, on this matter being reported to him, ceasing from his expedition and deferring all other affairs, sends a great part of the cavalry to pursue him, and commands that he be brought back; he orders that if he use violence and do not submit, that he be slain; considering that Dumnorix would do nothing as a rational man while he himself was absent, since he had disregarded his command even when present. He, however, when recalled, began to resist and defend himself with his hand, and implore the support of his people, often exclaiming that "he was free and the subject of a free state." They surround and kill the man as they had been commanded; but the Aeduan horsemen all return to Caesar.