DIOCLETIAN (Imp. Caesar M. Aurelius Valerius Diocletianus Augustus), ROMAN EMPEROR. – Born into a humble family in Dalmatia around 243, perhaps not far from Salona, he, like many of his fellow provincials from Illyricum, pursued a military career. Distinguished in the harsh wars conducted by Aurelian and Probus, he took part in the expedition of Emperor Carus against the Persians (283), holding the high rank of comes domesticorum, i.e., commander of the imperial guard. When the expedition was cut short by the sudden death of Carus, the Roman army retreated under the leadership of Carus’s young son, who had already been named colleague of the empire: Numerian. During the long march, Numerian was killed; the soldiers accused the praetorian prefect Arrius of the crime, and Diocletian, accepting this version of events, swiftly and brutally put Arrius to death with his own hand. He was then proclaimed emperor by the army on 17 September 284. The resistance that Carinus, the other son of Carus and still in Rome, prepared against him failed due to Carinus’s assassination at the hands of one of his own officers, and Diocletian was universally recognized as emperor. To the daunting task before him, Diocletian brought neither cultural preparation nor extensive administrative