His ascension to power was anticipated

During this time, gods, fortune tellers, and special humans were all commonplace in Greek and Roman myth. Diocletian thought he was one of these special individuals because a fortune teller had told him that he would reign on the day he killed a boar.

Numerian, the emperor and brother of Carinus, was found dead in 284, during that campaign, and his adoptive father, the praetorian prefect Aper, was charged with murder to take control. Diocletian announced his innocence of Numerian's murder when he made his first public appearance after being recognized as emperor by his soldiers and wearing imperial purple. When the acknowledged ruler of the Empire passed away, Diocletian accused a man by the name of Aper, which is Latin for "boar," of killing the late emperor. In truth, the former emperor had passed away from natural circumstances or had been struck by lightning, yet Aper felt guilty even though he was innocent. It was also true that he didn't want to keep waiting for the boar to arrive. However, with Aper's passing, Diocletian was freed of a potential rival and, in hindsight, his deed gained hallowed significance. Diocletian ascended to the throne after killing his boar.