99 Facts About Diocletian


Diocletian, nicknamed "Jovius", was Roman emperor from 284 until his abdication in 305.


Diocletian was born Diocles to a family of low status in the Roman province of Dalmatia.


The title was claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.


Diocletian's reign stabilized the empire and ended the Crisis of the Third Century.


Diocletian reigned in the Eastern Empire, and Maximian reigned in the Western Empire.


Diocletian secured the empire's borders and purged it of all threats to his power.


Diocletian defeated the Sarmatians and Carpi during several campaigns between 285 and 299, the Alamanni in 288, and usurpers in Egypt between 297 and 298.


Galerius, aided by Diocletian, campaigned successfully against Sassanid Persia, the empire's traditional enemy.


Diocletian led the subsequent negotiations and achieved a lasting and favorable peace.


Diocletian separated and enlarged the empire's civil and military services and reorganized the empire's provincial divisions, establishing the largest and most bureaucratic government in the history of the empire.


Diocletian established new administrative centres in Nicomedia, Mediolanum, Sirmium, and Trevorum, closer to the empire's frontiers than the traditional capital at Rome.


Not all of Diocletian's plans were successful: the Edict on Maximum Prices, his attempt to curb inflation via price controls, was counterproductive and quickly ignored.


Diocletian lived out his retirement in his palace on the Dalmatian coast, tending to his vegetable gardens.


Diocletian was born in Dalmatia, probably at or near the town of Salona, to which he retired later in life.


Diocletian was considered an Illyricianus who had been schooled and promoted by Aurelian.


The first time Diocletian's whereabouts are accurately established was in 282 when the Emperor Carus made him commander of the Protectores domestici, the elite cavalry force directly attached to the Imperial household.


Diocletian raised his sword to the light of the sun and swore an oath disclaiming responsibility for Numerian's death.


Diocletian asserted that Aper had killed Numerian and concealed it.


Diocletian was skilled in areas of government where Diocletian presumably had no experience.


Diocletian was not the only challenger to Carinus' rule; the usurper Julianus, Carinus' corrector Venetiae, took control of northern Italy and Pannonia after Diocletian's accession.


Diocletian's rule was unpopular, and it was later alleged that he had mistreated the Senate and seduced his officers' wives.


Diocletian exacted an oath of allegiance from the defeated army and departed for Italy.


Diocletian eventually made his way to northern Italy and made an imperial government, but it is not known whether he visited Rome at this time.


Diocletian dated his reign from his elevation by the army, not his ratification by the Senate, following the practice established by Carus, who had declared the Senate's ratification a useless formality.


Diocletian replaced the prefect of Rome with his consular colleague Bassus.


Diocletian later gave him the proconsulate of Africa and the post of urban prefect for 295.


At some time in 285 at Mediolanum, Diocletian raised his fellow-officer Maximian to the office of Caesar, making him his effective co-ruler.


Diocletian was in a less comfortable position than most of his predecessors, as he had a daughter, Valeria, but no sons.


Diocletian's co-ruler had to be from outside his family, raising the question of trust.


Around 287 Diocletian assumed the title Iovius, and Maximian assumed the title Herculius.


The Sarmatians requested that Diocletian either help them recover their lost lands or grant them pasturage rights within the empire.


Diocletian refused and fought a battle with them, but was unable to secure a complete victory.


Diocletian visited Syria Palaestina the following spring, His stay in the East saw diplomatic success in the conflict with Persia: in 287, Bahram II granted him precious gifts, declared open friendship with the Empire, and invited Diocletian to visit him.


Bahram II's gifts were widely recognized as symbolic of a victory in the ongoing conflict with Persia, and Diocletian was hailed as the "founder of eternal peace".


Diocletian invaded Germania through Raetia while Maximian progressed from Mainz.


On his return to the East, Diocletian managed what was probably another rapid campaign against the resurgent Sarmatians.


Diocletian might have been attempting to persuade them to ally themselves with Rome, thus reviving the old, Rome-friendly, Palmyrene sphere of influence, or to reduce the frequency of their incursions.


Diocletian broke off his tour of the Eastern provinces soon thereafter.


Some time after his return, and before 293, Diocletian transferred command of the war against Carausius from Maximian to Flavius Constantius, which he concluded successfully in 296.


Diocletian was Maximian's praetorian prefect in Gaul, and the husband to Maximian's daughter, Theodora.


Diocletian spent the spring of 293 travelling with Galerius from Sirmium to Byzantium.


Diocletian then returned to Sirmium, where he remained for the following winter and spring.


Diocletian campaigned successfully against the Sarmatians in 294, probably in the autumn.


Meanwhile, Diocletian built forts north of the Danube, part of a new defensive line called the Ripa Samartica, at Aquincum, Bononia, Ulcisia Vetera, Castra Florentium, Intercisa, and Onagrinum.


In 295 and 296 Diocletian campaigned in the region again, and won a victory over the Carpi in the summer of 296.


Later during both 299 and 302, as Diocletian was residing in the East, it was Galerius's turn to campaign victoriously on the Danube.


Diocletian returned to Syria in 295 to fight the revanchist Persian empire.


Diocletian moved into Egypt to suppress him, first putting down rebels in the Thebaid in the autumn of 297, then moving on to besiege Alexandria.


Later in 298, a triumphal column was erected in Alexandria to honor Diocletian, known as Pompey's Pillar.


Bureaucratic affairs were completed during Diocletian's stay: a census took place, and Alexandria, in punishment for its rebellion, lost the ability to mint independently.


Diocletian travelled south along the Nile the following summer, where he visited Oxyrhynchus and Elephantine.


Diocletian appears to have first invaded western Armenia, where he seized the lands delivered to Tiridates in the peace of 287.


Diocletian moved south into Roman Mesopotamia in 297, where he inflicted a severe defeat on Galerius in the region between Carrhae and Callinicum.


Diocletian was conservative in matters of religion, faithful to the traditional Roman pantheon and understanding of demands for religious purification, but Eusebius, Lactantius and Constantine state that it was Galerius, not Diocletian, who was the prime supporter of the purge.


Galerius, even more devoted and passionate than Diocletian, saw political advantage in the persecution.


Diocletian was willing to break with a government policy of inaction on the issue.


Diocletian found much to be offended by in Manichean religion: its novelty, its alien origins, its perceived corruption of Roman morals, and its inherent opposition to long-standing religious traditions.


Diocletian ordered that the deacon Romanus of Caesarea have his tongue removed for defying the order of the courts and interrupting official sacrifices.


Diocletian left the city for Nicomedia in the winter, accompanied by Galerius.


Diocletian believed that forbidding Christians from the bureaucracy and military would be sufficient to appease the gods, but Galerius pushed for extermination.


At the behest of his court, Diocletian acceded to demands for universal persecution.


Diocletian demanded that its scriptures be burned, and seized its precious stores for the treasury.


Diocletian was demonized by his Christian successors: Lactantius intimated that Diocletian's ascendancy heralded the apocalypse.


Diocletian entered the city of Rome in the early winter of 303.


Diocletian soon grew impatient with the city, as the Romans acted towards him with what Edward Gibbon, following Lactantius, calls "licentious familiarity".


Diocletian contracted a minor illness while on campaign, but his condition quickly worsened and he chose to travel in a litter.


Rumours that Diocletian's death was being kept secret until Galerius could assume power spread through the city.


The city was sent into mourning from which it recovered after public declarations that Diocletian was still alive.


In front of a statue of Jupiter, his patron deity, Diocletian addressed the crowd.


Diocletian declared that he needed to pass the duty of empire on to someone stronger.


Diocletian thus became the first Roman emperor to voluntarily abdicate his title.


Constantine had travelled through Palestine at the right hand of Diocletian, and was present at the palace in Nicomedia in 303 and 305.


In Lactantius's account, when Diocletian announced that he was to resign, the entire crowd turned to face Constantine.


Diocletian moved into the expansive Diocletian's Palace, a heavily fortified compound located by the small town of Spalatum on the shores of the Adriatic Sea, and near the large provincial administrative center of Salona.


Diocletian ordered Maximian, who had attempted to return to power after his retirement, to step down permanently.


Diocletian lived for four more years, spending his days in his palace gardens.


Diocletian saw his tetrarchic system fail, torn apart by the civil wars of his successors.


Diocletian heard of Maximian's third claim to the throne, his forced suicide, and his damnatio memoriae.


Diocletian saw his work as that of a restorer, a figure of authority whose duty it was to return the empire to peace, to recreate stability and justice where barbarian hordes had destroyed it.


Diocletian arrogated, regimented and centralized political authority on a massive scale.


Aurelian's achievements were ignored, the revolt of Carausius was backdated to the reign of Gallienus, and it was implied that the tetrarchs engineered Aurelian's defeat of the Palmyrenes; the period between Gallienus and Diocletian was effectively erased.


Diocletian took to wearing a gold crown and jewels, and forbade the use of purple cloth to all but the emperors.


Diocletian's subjects were required to prostrate themselves in his presence ; the most fortunate were allowed the privilege of kissing the hem of his robe.


Diocletian regulated his court by distinguishing separate departments for different tasks.


Altogether, Diocletian greatly increased the number of bureaucrats at the government's command; Lactantius claimed that there were now more men using tax money than there were paying it.


Diocletian's reforms shifted the governors' main function to that of the presiding official in the lower courts: whereas in the early Empire military and judicial functions were the function of the governor, and procurators had supervised taxation, under the new system and governors were responsible for justice and taxation, and a new class of, acting independently of the civil service, had military command.


On one occasion, Diocletian had to exhort a proconsul of Africa not to fear the consequences of treading on the toes of the local magnates of senatorial rank.


Whenever the imperial court would settle in one of the capitals, there was a glut in petitions, as in late 294 in Nicomedia, where Diocletian kept winter quarters.


Emperors in the forty years preceding Diocletian's reign had not managed these duties so effectively, and their output in attested rescripts is low.


The sharp increase in the number of edicts and rescripts produced under Diocletian's rule has been read as evidence of an ongoing effort to realign the whole Empire on terms dictated by the imperial center.


Partly in response to economic pressures and in order to protect the vital functions of the state, Diocletian restricted social and professional mobility.


The most that can be said about built structures under Diocletian's reign is that he rebuilt and strengthened forts at the Upper Rhine frontier, on the Danube, in Egypt and on the frontier with Persia.


The fifth-century pagan Zosimus, by contrast, praised Diocletian for keeping troops on the borders, rather than keeping them in the cities, as Constantine was held to have done.


Diocletian was led to devise a new system of taxation.


Diocletian's reforms increased the number of financial officials in the provinces: more rationales and magistri privatae are attested under Diocletian's reign than before.


Diocletian restored the three-metal coinage and issued better quality pieces.


Diocletian, therefore, issued his Edict on Coinage, an act re-tariffing all debts so that the nummus, the most common coin in circulation, would be worth half as much.


The Era of Martyrs, known as the Diocletian era, is a method of numbering years used by the Church of Alexandria beginning in the 4th century anno Domini and by the Coptic Orthodox Church of Alexandria from the 5th century to the present.


One of them recounts that Diocletian was originally a swineherd, and that in this part of his life, he was teased and abused by young Jews.