Titus Livius (Livy), The History of Rome, Book 8
Benjamin Oliver Foster, Ph.D., Ed.

18. a terrible year succeeded, whether owing¹ to the unseasonable weather or to man's depravity. The consuls were Marcus Claudius Marcellus and Gaius Valerius. [2] i find Flaccus and Potitus severally given in the annals, as the surname of Valerius; but it does not greatly signify where the truth lies in regard to this. [3] one thing, however, I should be glad to believe had been falsely handed down —and indeed not all the authorities avouch it —namely, that those whose deaths made the year notorious for pestilence were in reality destroyed by poison; still, I must set forth the story as it comes to us, that I may not deprive any writer of his credit. [4] when the leading citizens were falling ill with the same kind of malady, which had, in almost every case the same fatal termination, a certain serving —woman [5] came to Quintus Fabius Maximus, the curule aedile, and declared that she would reveal the cause of the general calamity, if he would give her a pledge that she should not suffer for her testimony. Fabius at once referred the matter to the consuls, and the consuls [6??] to the senate, and a pledge was given to the witness with the unanimous approval of that body. [7] she then disclosed the fact that the City was afflicted by the criminal practices of the women; that they who prepared these poisons were matrons, whom, if they would instantly attend her, they might take in the very act. [8] they followed the informer and found certain women brewing poisons, [p. 73]and other poisons stored away. These concoctions² were brought into the Forum, and some twenty matrons, in whose houses they had been discovered, were summoned thither by an apparitor. two of their number, Cornelia and Sergia, of patrician houses both, asserted that these drugs were salutary. [9] on the informer giving them the lie, and bidding them drink and prove her charges false in the sight of all, they took time to confer, and after the crowd had been dismissed they referred the question to the rest, and finding that they, like themselves, would not refuse the draught, they all drank off the poison and perished by their own wicked practices. [10] their attendants being instantly arrested informed against a large number of matrons, of whom one hundred and seventy were found guilty; [11] yet until that day there had never been a trial for poisoning in Rome. their act was regarded as a prodigy, and suggested madness rather than felonious intent. [12] accordingly when a tradition was revived from the annals how formerly in secessions of the plebs³ a nail had been driven by the dictator, and how men's minds, which had been distracted by dissension, had by virtue of that expiation regained their self —control, they resolved on the appointment of a dictator to drive the nail. [13] The appointment went to Gnaeus Quinctilius, who named Lucius Valerius master of the horse. The nail was driven and they resigned their posts.