stylistic:style_transfer
Sources

Tacitus makes use of the official sources of the Roman state: the Acta Senatus (the minutes of the sessions of the Senate) and the Acta Diurna (a collection of the acts of the government and news of the court and capital). He also read collections of emperors' speeches, such as those of Tiberius and Claudius. He is generally seen as a scrupulous historian who paid careful attention to his sources.

Tacitus cites some of his sources directly, among them Cluvius Rufus, Fabius Rusticus and Pliny the Elder, who had written Bella Germaniae and a historical work which was the continuation of that of Aufidius Bassus. Tacitus also uses collections of letters (epistolarium). He also took information from exitus illustrium virorum. These were a collection of books by those who were antithetical to the emperors. They tell of sacrifices by martyrs to freedom, especially the men who committed suicide. While he places no value on the Stoic theory of suicide and views suicides as ostentatious and politically useless, Tacitus often gives prominence to speeches made by those about to commit suicide, for example Cremutius Cordus ' speech in Ann. IV, 34–35.