September 13th is the anniversary of the death of the Roman emperor Titus (Titus Flavius Vespasianus), who reigned for barely more than two years. The date is known from Suetonius’ Life 11:
Excessit in eadem qua pater villa Id. Septb. post biennium ac menses duos diesque XX. quam successerat patri, altero et quadragesimo aetatis anno.
You can find a translation of the Life here:
He died in the same villa where his father had died before him, upon the Ides of September [the 13th of September]; two years, two months, and twenty days after he had succeeded his father; and in the one-and-fortieth year of his age.
Cassius Dio also gives an account of his death (Roman History 66.26), noting the rumor that Domitian was responsible for his demise:
After he had finished these exhibitions [at the Colosseum], and had wept so bitterly on the last day that all the people saw him, he performed no other deed of importance; but the next day, in the consulship of Flavius and Pollio, after the dedication of the buildings mentioned, he passed away at the same watering-place that had been the scene of his father’s death. 2 The common report is that he was put out of the way by his brother, for Domitian had previously plotted against him; but some writers state that he died a natural death. The tradition is that, while he was still breathing and possibly had a chance of recovery, Domitian, in order to hasten his end, placed him in a chest packed with a quantity of snow, pretending that the disease required, perhaps, that a chill be administered.
Both Suetonius and Cassius Dio refer to Titus’ cryptic last words. First, Suetonius:
Amidst all these favourable circumstances, he was cut off by an untimely death, more to the loss of mankind than himself. At the close of the public spectacles, he wept bitterly in the presence of the people, and then retired into the Sabine country, rather melancholy, because a victim had made its escape while he was sacrificing, and loud thunder had been heard while the atmosphere was serene. At the first resting-place on the road, he was seized with a fever, and being carried forward in a litter, they say that he drew back the curtains, and looked up to heaven, complaining heavily, “that his life was taken from him, though he had done nothing to deserve it; for there was no action of his that he had occasion to repent of, but one.” [neque enim exstare ullum suum factum paenitendum, excepto dum taxat uno] What that was, he neither disclosed himself, nor is it easy for us to conjecture. Some imagine that he alluded to the connection which he had formerly had with his brother’s wife. But Domitia solemnly denied it on oath; which she would never have done, had there been any truth in the report; nay, she would certainly have gloried in it, as she was forward enough to boast of all her scandalous intrigues.
Now, Cassius Dio, who also mentions the possibility that Titus was referring to Domitia, but adds that another report, that he meant his words to refer to his brother Domitian, is more persuasive to him:
At any rate, he rode off to Rome while Titus was still alive, entered the camp, and received the title and authority of emperor, after giving the soldiers all that his brother had given them. Titus, as he expired, said: “I have made but one mistake.” What this was he did not make clear, and no one else recognized it with certainty. Some have conjectured one thing and some another. 4 The prevailing view is that of those who say that he referred to his taking his brother’s wife, Domitia. Others — and these I am inclined to follow — say that what he meant as his mistake was that he had not killed Domitian when he found him openly plotting against him, but had chosen rather to suffer that fate himself at his rival’s hands, and had surrendered the empire of the Romans to a man like Domitian, whose character will be made clear in the continuation of my narrative. Titus had ruled two years, two months and twenty days, as has been already stated.
