Plutarch, Cicero
Bernadotte Perrin, Ed.

20. While Cicero was in this perplexity, a sign was given to the women who were sacrificing. The altar, it seems, although the fire was already thought to have gone out, sent forth from the ashes and burnt bark upon it a great bright blaze. The rest of the women were terrified at this, but the sacred virgins bade Terentia the wife of Cicero go with all speed to her husband and tell him to carry out his resolutions in behalf of the country, since the goddess was giving him a great light on this path to safety and glory. [2] So Terentia, who was generally of no mild spirit nor without natural courage, but an ambitious woman, and, as Cicero himself tells us¹ more inclined to make herself a partner in his political perplexities than to share with him her domestic concerns, gave him this message and incited him against the conspirators; so likewise did Quintus, his brother, and Publius Nigidius, one of his philosophical companions, to whom he made the most and greatest use in his political undertakings.

[3] On the following day the senate discussed the punishment of the conspirators, and Silanus, who was the first to be asked to give his opinion, said that they ought to be taken to prison and there suffer extremest punishment. All the senators acceded to his opinion one after the other, until it came to Caius Caesar,² who afterwards became dictator. At this time, however, he was a young man still and at the very beginning of his rise to power, but in his public policy and his hopes he had already entered upon that road by which he changed the Roman state into a monarchy. His designs were still unnoticed by the rest, [4] but to Cicero he had given many grounds for suspicion, and yet no hold which could lead to his conviction, although many were heard to say that he had come near being caught by Cicero, but had eluded him. Some, however, say that Cicero purposely overlooked and neglected the information against him through fear of his friends and his power, since it was clear to every one that the other conspirators would be included in Caesar's acquittal, rather than Caesar in their punishment.