Those who decry Tacitus for prejudice against the Empire forget that he is describing emperors who were indubitably bad. We have lost his account of Vespasian’s reign. His praise of Augustus and of Trajan was never written. The emperors whom he depicts for us were all either tyrannical or contemptible, or both: no floods of modern biography can wash them white. They seemed to him to have degraded Roman life and left no room for virtus in the world. The verdict of Rome had gone against them. So he devotes to their portraiture the venom which the fifteen years of Domitian’s reign of terror had engendered in his heart. He was inevitably a pessimist; his ideals lay in the past; yet he clearly shows that he had some hope of the future. Without sharing Pliny’s faith that the millennium had dawned, he admits that Nerva and Trajan have inaugurated ‘happier times’ and combined monarchy with some degree of personal freedom.
There are other reasons for the ‘dark shadows’ in Tacitus’ work. History to a Roman was opus oratorium, a work of literary art. Truth is a great but not a sufficient merit. The historian must be not only narrator but ornator rerum. He must carefully select and arrange the incidents, compose them into an effective group, and by the power of language make them memorable and alive. In these books Tacitus has little but horrors to describe: his art makes them unforgettably horrible. The same art is ready to display the beauty of courage and self-sacrifice. But these were rarer phenomena than cowardice and greed. It was not Tacitus, but the age, which showed a preference for vice. Moreover, the historian’s art was not to be used solely for its own sake. All ancient history was written with a moral object; the ethical interest predominates almost to the exclusion of all others. Tacitus is never merely literary. The [Greek: semnotes] which Pliny notes as the characteristic of his oratory, never lets him sparkle to no purpose. All his pictures have a moral object ’to rescue virtue from oblivion and restrain vice by the terror of posthumous infamy’. His prime interest is character: and when he has conducted some skilful piece of moral diagnosis there attaches to his verdict some of the severity of a sermon. If you want to make men better you must uncover and scarify their sins.