Caius Valerius Diocletianus, one of the most famous of the Roman emperors, was, as De Quincey says, "doubtless that man of iron whom the times demanded." He was born at Dioclea, in Dalmatia, some say at Salona, about A.D. 245 according to some, but others make him ten years older. His original name was Diocles, which he afterward changed into Diocletianus. He is said by some to have been the son of a notary, by others the freedman of a senator named Anulinus. He entered the army at an early age, and rose gradually to rank; he served in Gaul, in Moesia, under Probus, and was present at the campaign against the Persians, in which Carus, then emperor, perished in a mysterious manner. Diocletian commanded the household or imperial body-guards when young Numerianus, the son of Carus, was secretly put to death by Aper his father-in-law, while travelling in a close litter on account of illness, on the return of the army from Persia. The death of Numerianus being discovered after several days by the soldiers near Calchedon, they arrested Aper and proclaimed Diocletian emperor, who addressing the soldiers from his tribunal in the camp, protested his innocence of the death of Numerianus, and then upbraiding Aper for the crime, plunged his sword into the traitor's body. The new emperor observed to a friend that "he had now killed the boar," punning on the word Aper, which means a boar, and alluding to the prediction of a soothsayer in Gaul, who had told him that he would become emperor after having killed a boar (Vopiscus, in "Hist. Aug."). Diocletian, self-composed and strong-minded in other respects, was all his life an anxious believer in divination, which superstition led him probably to inflict summary punishment upon Aper with his own hands. He made his solemn entrance into Nicomedia in September, 284, which town he afterward chose for his favorite residence. Carinus, the other son of Carus, who had remained in Italy, having collected a force to attack Diocletian, the two armies met at Margum, in Moesia, where the soldiers of Carinus had the advantage at first, but Carinus himself being killed during the battle by his officers, who detested him for his cruelty and debauchery, both armies joined in acknowledging Diocletian emperor in 285. Diocletian was generous after his victory, and, contrary to the common practice, there were no executions, proscriptions, or confiscations of property; he even retained most of the officers of Carinus in their places.