Lentulus, therefore, designed no mean or trivial matter, for he had resolved to kill the whole senate, and as many other citizens as he could, to fire the city, and spare nobody, except only Pompey's children, intending to seize and keep them as pledges of his reconciliation with Pompey. For there was then a common and strong report that Pompey was on his way homeward from his great expedition. The night appointed for the design was one of the Saturnalia; swords, flax, and sulphur they carried and hid in the house of Cethegus; and providing one hundred men, and dividing the city into as many parts, they had allotted to every one singly his proper place, so that in a moment, many kindling the fire, the city might be in a flame all together. Others were appointed to stop up the aqueducts, and to kill those who should endeavour to carry water to put it out. Whilst these plans were preparing, it happened there were two ambassadors from the Allobroges staying in Rome; a nation at that time in a distressed condition, and very uneasy under the Roman government. These Lentulus and his party judging useful instruments to move and seduce Gaul to revolt, admitted into the conspiracy and they gave them letters to their own magistrates, and letters to Catiline; in those they promised liberty, in these they exhorted Catiline to set all slaves free, and to bring them along with him to Rome. They sent also to accompany them to Catiline, one Titus, a native of Croton, who was to carry those letters to him.
These counsels of inconsidering men, who conversed together over wine and with women, Cicero watched with sober industry and forethought, and with most admirable sagacity, having several emissaries abroad, who observed and traced with him all that was done, and keeping also a secret correspondence with many who pretended to join in the conspiracy. He thus knew all the discourse which passed betwixt them and the strangers; and lying in wait for them by night, he took the Crotonian with his letters, the ambassadors of the Allobroges acting secretly in concert with him.
By break of day, he summoned the senate into the temple of Concord, where he read the letters and examined the informers.
Junius Silanus further stated that several persons had heard Cethegus say that three consuls and four praetors were to be slain.
Piso, also, a person of consular dignity, testified other matters of the like nature; and Caius Sulpicius, one of the praetors, being sent to Cethegus's house, found there a quantity of darts and of armour, and a still greater number of swords and daggers, all recently whetted. At length, the senate decreeing indemnity to the Crotonian upon his confession of the whole matter, Lentulus was convicted, abjured his office (for he was then praetor), and put off his robe edged with purple in the senate, changing it for another garment more agreeable to his present circumstances. He thereupon, with the rest of his confederates present, was committed to the charge of the praetors in free custody.
It being evening, and the common people in crowds expecting without, Cicero went forth to them, and told them what was done, and then, attended by them, went to the house of a friend and near neighbour;for his own was taken up by the women who were celebrating, with secret rites the feast of the goddess whom the Romans call the Good, and the Greeks the Women's goddess. For a sacrifice is annually performed to her in the consul's house, either by his wife or mother, in the presence of the vestal virgins. And having got into his friend's house privately, a few only being present, he began to deliberate how he should treat these men. The severest, and the only punishment fit for such heinous crimes, he was somewhat shy and fearful of inflicting, as well from the clemency of his nature, as also lest he should be thought to exercise his authority too insolently, and to treat too harshly men of the noblest birth and most powerful friendships in the city; and yet, if he should use them more mildly, he had a dreadful prospect of danger from them. For there was no likelihood, if they suffered less than death, they would be reconciled, but rather, adding new rage to their former wickedness, they would rush into every kind of audacity, while he himself, whose character for courage already did not stand very high with the multitude, would be thought guilty of the greatest cowardice and want of manliness.
Whilst Cicero was doubting what course to take, a portent happened to the women in their sacrificing. For on the altar, where the fire seemed wholly extinguished, a great and bright flame issued forth from the ashes of the burnt wood; at which others were affrighted, but the holy virgins called to Terentia, Cicero's wife, and bade her haste to her husband, and command him to execute what he had resolved for the good of his country, for the goddess had sent a great light to the increase of his safety and glory. Terentia, therefore, as she was otherwise in her own nature neither tender-hearted nor timorous, but a woman eager for distinction (who, as Cicero himself says, would rather thrust herself into his public affairs, than communicate her domestic matters to him), told him these things, and excited him against the conspirators. So also did Quintus his brother, and Publius Nigidius, one of his philosophical friends, whom he often made use of in his greatest and most weighty affairs of state.