DIOCLETIAN (Imp. Caesar M. Aurelius Valerius Diocletianus Augustus), ROMAN EMPEROR. - Born of a humble family in Dalmatia around 243, perhaps not far from Salona, he made his way, like many of his compatriots from the Illyrian provinces, in the army. Having distinguished himself in the hard wars waged by Aurelian and by Probus, he took part in the expedition of the emperor Carus against the Persians (283), holding the high rank of comes domesticorum, that is, commander of the imperial guard. The expedition having been cut short by the sudden death of Carus, the Roman army turned back led by Carus's young son, already named colleague of the empire: Numerian. During the long march Numerian was killed, the voice of the soldiers laid the blame for the crime on the praetorian prefect Arrius, and D., accepting this version of the event, with a proceeding of barbarous promptness killed Arrius with his own hand, and was hailed emperor by the army (17 Sept. 284). The resistance that Carus's other son, Carinus, who had remained at Rome, was preparing to offer him, failed through the killing of Carinus at the hands of one of his officers, and D. was universally recognized as emperor. To the arduous task imposed upon him, D. brought no cultural preparation and not even a broad administrative experience, but a peasant's good sense, tenacity in his own ideas, a soldier's promptness in carrying out what had been decided, a high sense of duty, and a full dedication to it. The two gravest evils from which the Empire suffered were the ceaseless attempts at incursions by barbarians on the frontiers, and the lack of a rule for the imperial succession, so that the usurpations of emperors, elected in all the most anarchic forms, were likewise ceaselessly repeated, and wore down in sterile and ruinous internal struggles the insufficient forces of the Empire. To these two evils D. set himself to bring remedy. The vastness of the frontiers made a good guard of all of them difficult, and not only that, but in such troubled times even a victory was dangerous, since it had very often happened that victorious soldiers had hailed their commander as emperor, forcing him to assume the purple, and perhaps killing him some time later. D. began by naming himself a colleague, choosing a person of his own stamp, of humble family, Illyrian, a soldier, rougher than himself, endowed with personal valor and absolute loyalty: Maximian.
To him he entrusted the western provinces, keeping the eastern ones for himself; in this way it was less difficult for the emperor to hasten in person to the threatened frontier, and not to leave it to another to win the victory.
Having found this expedient good, some years later (293) he proceeded to a more radical reform that was to eliminate the uncertainty of the succession. He named two Caesars attached to the two Augusti, invested with authority superior to that of any other magistrate or general and destined to become Augusti when these should be lacking. The succession was in this way automatic, and the risks of usurpations should in theory have disappeared. A single criterion was to preside over the choice: the adoption of the most suitable, taking no account of ties of kinship. Conversely, a kind of fictitious kinship was instituted among the four sovereigns, the two Augusti calling themselves brothers and the two Caesars their sons. The partition was purely administrative, nor was it to encroach upon the unity of the Empire, because the authority of the elder of the Augusti was to prevail over all.
The Empire therefore ceased to be a kind of extraordinary magistracy, and became a sort of college to which one acceded by co-optation. The two great electors, the senate and the army, were eliminated entirely, and since they had hitherto acted as representatives of the Roman people, the Roman people was no longer the master of that state which nevertheless continued to call itself the res publica Romanorum.
The concept and function of the imperial dignity having thus been radically changed, there was no longer any reason not to assume fully the character and the outward manifestations of the absolute sovereign, with the ceremonial taken over from that of the oriental courts.
An ingenious and sound construction, but of a certain naive schematicism that did not withstand the complicated and egoistic psychology of men. The results in any case were good at the beginning: victories on all the frontiers, internal security, some twenty years of tranquillity. The one who lost by it was Rome, which ceased to be the seat of the Empire. All four sovereigns kept themselves in seats closer to the frontiers: D. at Nicomedia, in Bithynia, Maximian at Milan, and the two Caesars even further forward: Galerius at Sirmium on the Danube, Constantius Chlorus at Trier on the Rhine. The four cities had to be equipped so as to be able to serve as capitals, and the multiplication of courts and of the bureaucracy, as well as the increase of the army, came to weigh rather heavily on the budget of the State. An attempt was made to remedy this with radical reforms in the tributary system. Wealth consists of landed property and of the productive capacity of human and animal labor: these two sources of wealth are obliged to yield a part of their product to the State through the two taxes of the ingatio (land tax) and the capitatio (personal tax). With the tributary reorganization there is also to be connected a Diocletianic attempt aimed at obtaining a constancy and a reasonableness in the prices of goods and of works, an attempt that was not a novelty in the ancient world, but that had never until then been tried with such meticulous breadth. The relative edict is preserved in many epigraphic copies found in several cities of the eastern provinces (only one in Italy), none complete.
As regards religious policy, D., a sincerely religious spirit, sought to restore the ancient faith and the ancient Roman cult, on which the loyal observance of the subjects toward the double imperial dynasty was also to rest: that of D. is called Jovian and those of Maximian Herculian, and it reproduces in a certain way on earth the supreme celestial hierarchy: Jupiter, divine intelligence and will, Hercules, executor of that will. Religions other than the official one were tolerated by ancient practice of the Roman government, but watched and also repressed, if judged too aberrant from the prescriptions of the State religion. Christianity could find itself in such a condition, and if in the early years of D.'s reign it was not molested, there came later the moments of persecution. According to the Christian writers, the pertinacious and insistent counselor of measures of rigor would have been the Caesar Galerius, a rough and superstitious soldier and the son of a fanatical priestess of barbaric cults.
The actual persecution was reached by degrees. At first measures began to be taken against the Christians who served in the army, probably provoked by the refusals of Christian soldiers to obey orders that rightly or wrongly they deemed contrary to their conscience. The soldiers were enjoined to pay homage to the national divinities, on pain otherwise of the missio ignominiosa, expulsion from the army. Capital sentences seem to have been rare.
The same provisions were then taken for civil employees; it was not yet a bloody persecution, to which D., both by temperament and from having seen its futility, did not wish to come. But through the insistences of Galerius and through a response of the oracle of Apollo Didymaios at Miletus, the prescriptions of Valerian were brought back into force: destruction of the sacred books and of the churches, confiscation of their property, arrest of the Christian hierarchies.
It happened that the demolition of the church of Nicomedia was followed by a fire in the imperial palace, and the fire was held to be arson and the work of the Christians. And then matters reached the point of an order that all the inhabitants of the Empire should perform a public act of worship to the official divinities of the State, and that refusal to obey should be punished (503). The relevant edict, binding, as always happened, on all four rulers, was enforced with greater or lesser intensity in the various regions: very mildly by Constantius Chlorus, most harshly by Galerius and also by D., who always took seriously whatever he had decided to do. The failures of the previous persecutions now obliged them to be more radical and more ruthless. And many of the most illustrious martyrs whom we know were victims of this last persecution.
But D. was not a persecutor for long. Eager to witness in his lifetime the regular functioning of the system he had devised for the succession, he resolved at a certain point to renounce the Empire and to impose the same renunciation on his colleague Maximian. On 1 May 305 the two Augusti abdicated, and the two Caesars took their place. Two new Caesars were appointed, chosen from outside the families of the rulers. D. withdrew into private life in the great palace he had built near Salona, and within which is nestled the oldest part of the city of Split, from which he came forth once to try to restore order among successors and usurpers (the conference of Carnuntum). It is not known precisely in what year or how M. died.
Bibliography9 works
Roberto Paribeni
ICONOGRAPHY
G. Malalas (12, p. 306) describes D. as tall of stature, with grey hair and beard, white skin, blue eyes, a strong nose. The various coin types agree on the fundamental physiognomic features: a square head, a short nose forming an angle with the forehead, a protruding chin, a full neck, a robust nape (J. J. Bernoulli, Römische Ikonographie, II, III, Stuttgart 1894, p. 193 ff.). Of the sculptural portraits only the following can be considered certain: a statue in a toga (Rome, Villa Doria Pamphili) with a head belonging to it (later detached, reworked and passed into the antiquarian trade); a double herm, with Saturn, formerly in the Jerichau collection, Rome; a colossal head with a civic crown, from Nicomedia (K. Dörner, Ein neuer Porträtkopf des Kaisers Diohletien, in Die Antike, 17 [1941], p. 142); two porphyry reliefs, in the Vatican Library (R. Delbrück, Antike Porphyrwerke, Berlin-Leipzig 1932, p. 35) and at St. Mark's, Venice (ibid., p. 36); the clipeate image on the frieze in the interior of the Mausoleum of Split (ibid., p. 61). — See pl. XCVIII.
