DIOCLETIA'NUS, CAIUS VALERIUS, was born at Diodes, in Dalmatia, some say at Salons, about A.D. 215 according to some, but others make him ten years older. His original name was Diodes, which he afterwards changed into Diocletianua. 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 Nicosia under Probua, and was present at the campaign against the Persians, in which Carue perished in a mysterious manner. Diocletian commanded the house hold or Imperial bodyguards when young Numerianua, 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 Nnmerianua 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 Nume Annus, and then upbraiding Aper for the crime, plunged his sword into his body. The new emperor observed to a friend that "he had now killed the bear," punning on the word Aper, which means a boar, and alluding to the prediction of a soothsayer in Gaul, who bad told him that be 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 divina tion, which superstition led him probably to inflict summary punish ment upon Aper with his own hands. He made his solemn entrance into Nicomedia in September, 231, which town he afterwards chose for his favourite 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 Nicosia, where the soldiers of Cariuus bad 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 235. 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. (Aurelius Victor.) Diocletian on assuming the imperial power found the empire assailed by enemies in various quarters, on the Persian frontiers, on the side of Germany and of Illyricum, and in Britain ; besides which a serious revolt had broken out in Gaul among the rural population, under two leaders who had assumed the title of emperor. To quell the dis turbance in Gaul, Diocletian sent his old friend Maximianus, a native of Pannonia, and a brave but rude uncultivated soldier. Maximianus defeated the Bagaudi, for such was the name the rustic insurgents had assumed. In the year 280, Diocletian chose Maximianus as his colleague in the empire, under the name of Marcus Valerius Maxi mianus Augustus, and it is to the credit of both that the latter continued ever after faithful to Diocletian and willing to follow his advice. Maximianus was stationed in Gaul and on the German frontier to repel invasion; Diocletian resided chiefly in the Ewa, to watch the Persians, though he appears to have visited Rome in the early part of his reign. About 237 the revolt of Carausius took place. In the following year Maximiauus defeated the Germans near Treviri, and Diocletian himself marched against other tribes on the Rhmtian frontier; the year after he defeated the Sarmatians on the lower Danube. In the same year, 239, peace was made between Carausius
and the two emperors, Carausius being allowed to retain possession of Britain. In 290 Maximianus and Diocletian met at Milan to confer together on the state of the empire, after which Diocletian returned to Nicomedia. The Persians soon after again invaded Mesopotamia and threatened Syria, the Quinquegentiaoi, a federation of tribes in the Mauritania Cwsariensis, revolted, another revolt under one Achilimus broke out in Egypt, another in Italy under a certain Julianus. Diocletian thought it necessary to increase the number of his colleagues in order to face the attacks in the various quarters. On the 1st of March 292, or 291 according to some chronologists, he appointed Galerius as Cmaar, and presented him to the troops at Nicomedia. At the same time Maximianus adopted on his part Constantius called Chlorus. The two Cmsars repudiated their respective wives; Galerius married Valeria, Diecletian's daughter, adding to his name that of Valerianua ; and Constantius married Theodora, daughter of Maximianus. Galerius was a native of Dada, and a good soldier, but violent and cruel ; he had been a herdsman in his youth, for which lie has been styled, in derision, Armentarius. The two Cmsars remained subordinate to the two Augusti, though each of the four was entrusted with the administration of a part of the empire. Diocletian kept to himself Asia and Egypt; Maximianus had Italy and Africa ; Galerius, Thrace and Illyricum ; and Con atantitr had Gaul and Spain. But it was rather an administrative than a political division. At the head of the edicts of each prince were put the names of all the four, beginning with that of Diocletian. Diocletian resorted to this arrangement probably as much for reasons of internal as of external policy. For nearly a hundred years before, ever since the death of Commodua, the soldiers had been in the habit of giving or selling the imperial crown, to which any general might aspire. Between thirty and forty emperors had been thus successively made and unmade, many of whom only reigned a few months. By fixing upon four colleagues, one in each of the great divisions of the empire, each having his army, and all mutually checking one another, Diocletian put a stop to military insolence and anarchy. The empire was no longer put up to sale, the immediate and intolerable evil was effectually cured, though another danger remained, that of disputes and wars between the various sharers of the imperial power; still it was a smaller danger and one which did not manifest itself so long as Diocletian remained at the helm. Writers have been very free of their censure upon this emperor for parcelling, as they call it, the empire; but this was the only chance there was of preventing ite crumbling to pieces. Italy, and Rome, in particular, lost by the change : they no longer monopolised the wealth and power of the world, but the other provinces gained. The empire was much too large for one single man or a single central administration, under the dwindled influence of the Roman name, and amidst the numerous causes of local dissension and discontent, private ambition, social corruption, and foreign hostility, that had accumulated for three centuries, since the time of Augustus.