Livy is not renowned for his irony or for his wit. But he has both- and he can use both destructively- both to write about and to write around tyranny. There is a wonderful example in the fourth book of his history, concerning a minor Roman hero Cossus. Cossus was a hero in a battle against other Italians- seizing their general's arms and striking down their leader. He was awarded the right of putting the arms of that vanquished general inside the temple of Jupiter. But Livy faced a real problem- a problem to do with the definition of the arms that might be placed in the temple- traditionally in his own day that was the consul's prerogative. Fair enough, you might say things had changed: but Livy faces another problem on the one side we have the ancient chroniclers and on the other the temple records, from the temple of Jupiter. But examine closer what Livy says about those records in the temple and we notice this important line- put in I'm sure by accident- that it was Augustus Caesar himself who found the name of Cossus with the inscription consul beside it, after he had renovated it, surely Livy says it would be 'sacrilege to deprive Cossus of so great a witness to his spoils as Caesar, the restorer of that very shrine'. (4.20)
What Livy then does is unfold every reason why Cossus could not have been consul in that year. Other records in Rome, held in the temple of Moneta, do not show him holding the consulship in that year. Great historians like Licinius Macer have followed them and how they got it wrong is, a lovely touch, 'anybody's guess'. We can't shift the date of the battle- as we know that Cossus's actual later consulship was many years later 'within a three year period in which there were no wars at all' (4.20). Three years later he did fight another notable cavalry action as a military tribune but that is an independent story- and then Livy finishes his account by noting that
In all this there is room for conjecture, though in my own view it is unneccessary; for one need hardly attend to other people's guesses when the man himself who fought the battle having laid his new won spoils in their sacred resting place, in the visible presence of Romulus and Jupiter to whom he dedicated them- awful witnesses whom no forger would take lightly- inscribed his name as Aulus Cornelius Cossus, consul.
Of course Livy wants us to conjecture- that's why he has included all the other evidence above- and he wants us to link Augustus's restoration of the temple to Cossus's distinction. All the sources point one way and a newly restored temple points the other way- faith in Caesar means that we must beleive the temple mustn't we.
I don't think for a moment that Livy believed that Augustus faked this inscription deliberately- there isn't much I can imagine Caesar gaining from such a forgery about a battle long gone. But I do think that Livy is making a point about tyranny. Augustus made a mistake- but because he made a mistake- presuming that the ancient writing must have referred to Cossus consul- everyone else in Rome must believe that Cossus was the consul when all the evidence and an earlier meticulous account from Livy suggests that he wasn't. We have everything on one side and the word of Augustus on the other- but it is impossible now in Rome to not take the word of Augustus seriously- even when it commits a forgery (perhaps an honest one) in the temple of Jupiter with Romulus watching on. Both religion and truth are here the servants of tyranny- history or our perception of it twists around the finger of the emperor and ultimately we must believe, because he has said so, that Cossus was a consul- even though we know he is not.
That little anecdote I think captures perfectly the dilemmas that Livy and later historians faced- and the mode that they confronted them with. For resistance to tyranny was accomplished both by Livy, and his later successor Tacitus, using irony. For Tacitus this became the chief tool of history- because he wrote about the imperium- Livy was writing about the republic so his tone was more celebratory but I think in this piece of writing we see what a Livyan history of the Principate might have looked like. It would have been ironic- it would have been aware of the way truth vanishes at the tyrant's throne and it would have been, in that sense Tacitean.