20 November 284: Diocletian puts Aper to the sword

Commander avenges the death of the emperor Numerian


It was the autumn of AD 284, and the Roman army was marching home. After a successful campaign against the Persians, during which the emperor Carus had unfortunately died (reportedly, after being struck by lightning), the Romans were returning west. The forces were led by Carus’s son, Numerian.

But something strange was going on. Numerian had not been seen since they had left Emesa (now called Homs, in Syria). When the soldiers asked where he was, his attendants claimed that he had an eye infection and “must protect his weakened eyes from the wind and the sun”. And the soldiers could not help noticing that, from the coach where Numerian was supposedly recovering, there drifted an increasingly disgusting stench.

Eventually, when they reached Nicomedia (in what is now Turkey) on 20 November, the truth was discovered. Numerian was dead: murdered, some said, by his own father-in-law, Aper.

“Then all fell upon Aper, whose treachery could no longer be hidden, and they dragged him before the standards in front of the general’s tent,” records the Historia Augusta. “Then a huge assembly was held and a tribunal, too, was constructed.” The question was simple: “Who would be the most lawful avenger of Numerian and who could be given to the commonwealth as a good emperor?”

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The answer, it turned out, was a 40-year-old officer from Dalmatia, Diocletian, who commanded Numerian’s household troops. Diocletian duly stepped forward and drew his sword. Pointing to Aper, he said loudly: “It is he who contrived Numerian’s death” – and then buried his blade in Aper’s chest. It was, by any standards, a dramatic beginning for a Roman emperor. | Written by Dominic Sandbrook

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