Who was Diocletian? Everything You Need to Know

Quick Facts

Also Known As: Diocles

Died At Age: 66

Family:

Spouse/Ex-: Prisca

Born Country: Roman Empire

Emperors & Kings Ancient Roman Men

Died on: December 3, 311

place of death: Split

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Childhood & Early Life

Diocletian was born Diocles on December 22, 244, near Salona, Dalmatia (present-day Croatia). According to an Ancient Roman historian named Flavius Eutropius, most writers described Diocles as ‘the son of a scribe.’ Other set of records state that his father was a freedman under a senator named Anulinus.

Diocletian joined the military and worked his way up the ladder. He became the commander of Emperor Carus’ elite cavalry force. His role as the Roman cavalry commander led him to be a part of Carus’ Persian campaign in 283.

Carus died under mysterious circumstances during his campaign against Persia. Following his death, his sons Numerian and Carinus assumed power in the eastern and western provinces respectively.

In November 284, Numerian was found dead by the soldiers. After his death, a prefect named Aper attempted to garner the support of the generals and councilmen in order to seize power. However, Diocletian was chosen unanimously as the emperor of the eastern provinces. On November 20, 284, the army gathered near Nicomedia where Diocletian raised his sword and swore to avenge Numerian’s death. He killed Aper in front of the army, claiming that Aper had killed Numerian.

After his accession, Diocletian entered into conflict with Carinus. The conflict between Diocletian and Carinus culminated when their armies met across River Margus. In the ensuing ‘Battle of the Margus,’ Carinus was killed by his own men as he was unpopular among his men right from the beginning. Following the death of Carinus, armies of both the eastern and western provinces acclaimed Diocletian as the emperor.

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Rule & Reforms

Shortly after becoming the sole emperor of the Roman Empire, Diocletian appointed his fellow-officer Maximian as the co-emperor. The sharing of power between two or more was not new in the Roman Empire because of its colossal size.

In 293, Maximian gave the office of caesar (junior emperor) to Constantius Chlorus. In the same year, Diocletian appointed Galerius as the caesar of the eastern provinces. With the appointment of Galerius and Constantius, a tetrarchy was formed to divide the empire administratively. While Galerius was assigned Syria, Palestine, and Egypt, Constantius was assigned Britain and Gaul.

Diocletian’s successful campaign against the Sarmatians in 294 kept the Sarmatians from entering the Danube provinces. He also built forts at Aquincum, Castra Florentium, Bononia, Intercisa, Ulcisia Vetera, and Onagrinum as part of the empire’s new defensive system called ‘Ripa Sarmatica.’ By the end of his reign, Diocletian had built walled towns, highways, bridgeheads, and forts to secure Danube, an area that was deemed difficult to defend.

Diocletian increased the number of bureaucrats. According to historian Warren Treadgold, the number of men in the civil service increased from 15,000 to 30,000. He also increased the number of provinces from 50 to almost 100. The provinces were further divided into twelve dioceses which were governed by specially appointed officials.

Reforms in the empire’s provincial structure led to an increase in the number of governors who ruled over smaller regions. Apart from collecting taxes and serving as judges, the governors were also expected to supervise the town councils.

During his reign, Diocletian gave utmost importance to military. The military reforms were aimed at providing adequate manpower, supplies, and infrastructure to the empire’s defense system. The number of men in the army increased from 390,000 to 580,000, while the number of men in the navy increased from 45,000 to 65,000.

A large portion of the imperial budget was spent on the military. Since the size of the empire’s armed forces kept growing, it became increasingly difficult for Diocletian to pay his soldiers and other men associated with the military. Fearing civil conflict and open revolt should he fail to pay his men, Diocletian came up with a new tax system to keep the money flowing.

Two new taxes namely ‘capitatio’ and ‘iugum’ were introduced by Diocletian. While ‘iugum’ was levied on a unit of cultivable land, ‘capitatio’ was levied on individuals. Assessments on the new tax system were made once in every five years. Diocletian’s reforms in the tax system increased the number of financial officials.

Italy, which was free of taxes for a very long time, was not exempted from the new tax system. However, the city of Rome was exempt from the taxes. Provinces south of Rome were relatively less taxed.

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Diocletian also revamped the empire’s currency. He reintroduced three-metal coinage and issued coins of better quality. Five types of coins were minted as part of the new system. However, the state incurred losses while minting these new coins as the nominal value of the new issues was lower than the cost of the metals used to mint the coins.

In 301, Diocletian issued an edict on coinage in an attempt to reduce the rotation of gold coins. A couple of months after the issuance of the edict on coinage, Diocletian issued the famous ‘Edict on Maximum Prices’ which is preserved to date. In the edict, the emperor blamed the greed of the merchants for the empire’s pricing crisis.

Christian Persecution

‘Great Persecution’ also known as the ‘Diocletianic Persecution’ was the most severe persecution of Christians in the history of Roman Empire. In 299, the Roman emperors participated in a sacrificial ceremony in order to predict the future. As part of the ceremony, Christians were sacrificed to Roman gods, a practice that was prevalent in the empire since the 250s.

In the early 300s, a deacon called Romanus of Caesarea defied the order of the courts and interrupted official sacrifices. As a consequence, his tongue was cut out at the emperor’s command. Romanus was then tortured in many ways in prison before he was strangled to death.

Though Diocletian believed that the Roman gods could be appeased by forbidding the Christians from the bureaucracy and armed forces, Galerius wanted to exterminate the Christians. The two men argued over the issue and finally decided to seek the advice of Apollo’s oracle. However, the oracle said that Apollo (Olympian deity) refrained from providing advice owing to the impious on Earth. Subsequently, the members of the court convinced Diocletian that the impious could only refer to the Christians.

In 303, a series of edicts revoking legal rights of the Christians were issued across the Roman Empire. The edicts also ordered the destruction of Christian churches and forbade Christians from assembling for worship.

In February 303, a part of the Imperial palace was destroyed by a fire and Christians along with the eunuchs of the palace were blamed for it. In the executions that followed, Peter Cubicularius was scourged and boiled to death over an open flame. The executions continued until April 303 during which six individuals including Anthimus of Nicomedia were killed by decapitation.

When Constantius Chlorus’ son Constantine became the emperor in 306, he revoked the edicts that persecuted the Christians. Under his rule, Christianity became Roman Empire’s preferred religion. It eventually became the empire’s official religion in 380.

Abdication & Death

In 304, Diocletian contracted an illness which worsened over the next few months. He then refrained from appearing in public until March 305 when he was barely recognizable. On May 1, 305, Diocletian called for a meeting. He met his generals and representatives from distant legions at the same hill where he was proclaimed emperor. With tears rolling down from his eyes, he told them of his decision to retire, thus becoming the first Roman emperor to abdicate his title voluntarily.

Diocletian returned to his homeland Dalmatia where he started spending time in his palace. He spent the last few years of his life in his palace gardens even as he watched the tetrarchy fail because of the ambitions of his successors. He passed away on December 3, 312, and his mortal remains were buried in his palace. His tomb was later turned into a church which stands today as ‘Cathedral of St. Domnius.’

Diocletian Biography