Diocletian

NAME Gaius Aurelius Valerius Diocletianus

WHAT FAMOUS FOR Diocletian became Roman emperor in 284 AD and implemented major reforms that stabilized the Roman Empire, effectively ending the Crisis of the Third Century.  He is also known for his persecution of Christian

BIRTH Born around 244 AD in the Roman province of Dalmatia (modern-day Croatia).

FAMILY BACKGROUND Diocletian came from a modest, possibly Illyrian or Dalmatian family with no known aristocratic ties. His father may have been a scribe or a former slave, which made his rise to emperor all the more remarkable.

CHILDHOOD Little is known about Diocletian’s early life, but he likely grew up in a military environment, which helped shape his later career.

EDUCATION Diocletian was well-versed in military strategy and administration, but there is little evidence that he received a formal classical education. His practical knowledge and leadership skills, however, were instrumental in his rise to power.

CAREER RECORD Diocletian had a distinguished military career, rising through the ranks of the Roman army, eventually becoming commander of the imperial bodyguard.  

284 Proclaimed emperor by his troops.  Implemented significant administrative and military reforms, dividing the empire into four regions, each ruled by a Tetrarch (two senior Augusti and two junior Caesares). 

305 Abdicated and retired to his palace near Spalatum (Split, Croatia. He was the first Roman emperor to voluntarily retire.

APPEARANCE Diocletian was often depicted in statues and coins with a stern, commanding expression, reflecting his authoritative rule. Ancient sources describe him as physically imposing and well-built, befitting a career soldier.

Head of Diocletian- https://www.getty.edu/art/collection/object/103TG7

FASHION As emperor, Diocletian adopted luxurious, ornate clothing, favoring the purple robes and gold-embroidered tunics that symbolized imperial power. He also reinforced the tradition of emperors being treated as divine figures, influencing imperial fashion for centuries.

CHARACTER Diocletian was known for his discipline, efficiency, and organizational skills. He was a pragmatic ruler, willing to take drastic measures to stabilize the empire.  He could be ruthless when necessary, particularly in his persecution of Christians

SPEAKING VOICE Diocletian was known for his commanding presence and ability to inspire loyalty among his troops and officials. His speeches likely carried the authoritative and forceful tone expected of a Roman emperor.

SENSE OF HUMOUR Though known for his strict and sometimes ruthless rule, Diocletian had a sense of humour, especially in his later years. When urged to return to power after his retirement, he reportedly replied, "If you could see the cabbages I have planted with my own hands, you would not ask me to return to the troubles of empire." This response suggests a man who had come to appreciate the simple joys of life over the weight of governance.

RELATIONSHIPS Diocletian was married to Prisca, and together they had a daughter, Galeria Valeria. The marriage likely took place sometime in the 260s or 270s AD, before Diocletian became emperor in 284 AD.

Below are historical reenactors at Diocletian's Palace; actors playing Diocletian and Prisca are at centre

https://www.flickr.com/photos/184393744@N06/49358667147/

His reign was marked by strong political relationships, most notably with Maximian, whom he appointed as co-emperor to help manage the vast Roman Empire. 

In 285 AD, he and Maximian passed laws making monogamy the only legal form of marriage, reinforcing traditional Greek and Roman values long before Christianity became the dominant faith of the empire.

MONEY AND FAME Diocletian was one of the most powerful men of his time, ruling from 284 to 305 AD. He is best known for establishing the Tetrarchy, a system that divided the empire among four rulers to improve administration. However, despite his wealth and influence, he voluntarily abdicated in 305 AD, choosing a quiet life of retirement rather than clinging to power. His economic reforms, including efforts to curb inflation with the Edict on Maximum Prices, were ambitious but ultimately unsuccessful.

FOOD AND DRINK After stepping down as emperor, Diocletian famously retired to his palace in Split (modern-day Croatia), where he dedicated himself to farming. He took great pride in his vegetable gardens, especially his cabbages, and found solace in the simplicity of rural life. His love for agriculture suggests that, despite once ruling an empire, he had a deep appreciation for the earth’s bounty.

MUSIC AND ARTS As emperor, Diocletian was a patron of Roman traditions. He oversaw large-scale architectural projects, including his grand palace in Split, which incorporated grand columns and elaborate decorations reflecting the grandeur of Roman imperial style. Public entertainment, such as gladiatorial games and theatrical performances, flourished under his rule.

LITERATURE Diocletian was not known for being a writer or philosopher himself, but he surrounded himself with advisors and intellectuals. His reign was a time of legal and administrative codification, and he issued numerous imperial edicts that shaped Roman law. The Edict on Maximum Prices was one of his most famous writings, attempting to regulate the economy through strict price controls.

A fragment of the Edict on Maximum Prices (301), on display in Berlin By Matthias Kabe

Diocletian showed a deep love for traditional higher culture, which was evident in his opposition to Christian intellectuals and teachers who, in his view, had no right to engage with classical works like those of Homer

NATURE Diocletian's deep appreciation for nature became evident after his retirement. He settled in his palace on the Dalmatian coast, where he immersed himself in farming. His love for gardening, especially tending to vegetables, highlights a man who found peace in the natural world after decades of military and political struggles.

HOBBIES AND SPORTS Diocletian's primary hobby after retirement was gardening. However, during his rule, he promoted physical strength and military discipline, essential for maintaining Rome’s vast empire. Gladiatorial combat and chariot racing were the premier sports of his time, and as emperor, he would have presided over many such events.

SCIENCE AND MATHS Diocletian's reign saw advancements in Roman engineering and administration. His economic policies attempted to use mathematical principles to regulate pricing and wages, though with limited success. Additionally, his construction projects, including roads, aqueducts, and fortifications, demonstrated Rome’s engineering prowess. His decision to divide the empire into more manageable administrative regions was a strategic application of governance and logistics.

REIGN Diocletian was one of those rare historical figures who not only changed the course of history but also had the good sense to know when to walk away from it. Ruling the Roman Empire from 284 to 305 AD, he pulled off the impressive feat of stabilizing an empire that had been tearing itself apart for decades, introduced a complex system of shared rule, persecuted Christians with terrifying enthusiasm, and then—perhaps most astonishingly—retired. And not in the "I shall serve as a wise elder statesman" sense, but in the "I am going to grow vegetables now, please leave me alone" sense. 

One of Diocletian’s greatest achievements was the Tetrarchy, a system so well thought-out it lasted all of five minutes after he retired. The idea was that the empire was simply too large and chaotic for one man to rule, so he divided it into two halves, each governed by an Augustus (senior emperor) and a Caesar (junior emperor). Diocletian took the East (the richer, more civilized part), while his trusted colleague Maximian took the West (the colder, muddier, more likely-to-be-invaded part).

On paper, this system was supposed to ensure smooth successions and prevent civil wars. In practice, as soon as Diocletian was out of the picture, his successors promptly ignored the whole thing and went back to the traditional Roman pastime of murdering each other for power.

Diocletian, realizing that Rome was still trading on its name rather than its usefulness, moved administrative capitals closer to the empire’s frontiers. He built a sprawling palace in Nicomedia (modern-day Turkey) and later, his retirement home in Dalmatia (modern-day Croatia), which turned out to be so well-built that it still stands today. The new regional capitals allowed for better governance, but also reinforced the fact that Rome itself was becoming increasingly irrelevant in the grand scheme of things.

The Roman army under Diocletian became a stronger, more disciplined force. He reorganized it into smaller, mobile units that could respond quickly to threats. He also made sure that the military was well-funded, which in Roman terms meant squeezing every last coin out of the tax-paying population (more on that in a moment). These reforms helped secure Rome’s borders and fend off invasions—at least while Diocletian was in charge.

He introduced the capitatio-iugatio system, which taxed both land and individuals, ensuring that no one escaped paying their fair share. In theory, it made taxation more efficient. In reality, it was just as unpopular as you’d expect.

Inflation had been running wild, so in 294 AD, Diocletian reformed the currency, stabilizing silver and gold values and introducing new coins. This was one of his more successful policies, at least for a while.

In 301 AD, Diocletian attempted one of the most ambitious (and widely ignored) economic policies in history: the Edict on Maximum Prices. It set price ceilings for everything from grain to shoes to labor wages. Merchants, naturally, responded by either ignoring it or taking their goods to the black market. Rather than solving the crisis, it made things worse. Some people were executed for violating the law, but the law itself was quietly abandoned soon after.

If there’s one thing Diocletian is notorious for, it’s the Diocletianic Persecution, the most intense and organized persecution of Christians in Roman history. Beginning with his Edict Against the Christians on February 24, 303 AD, he ordered churches to be destroyed, sacred texts to be burned, and Christians to renounce their faith or face execution. By 304, all Christians were required to make sacrifices to the Roman gods—or die. However, instead of disappearing, Christianity only grew stronger in response.

In a move completely unheard of for Roman emperors (who usually left office via assassination), Diocletian voluntarily retired in 305 AD. He withdrew to his luxurious palace in Dalmatia, where he spent his days tending to his gardens and, by all accounts, being quite content.

PHILOSOPHY & THEOLOGY Diocletian was deeply committed to the traditional Roman religious system, believing that the prosperity of the empire depended on the favor of the gods. 

His devotion to Roman polytheism led to one of the most infamous persecutions in history. On February 24, 303, he issued his first Edict against the Christians, initiating the Diocletianic Persecution, the most severe crackdown on Christianity in Roman history. By early 304, he mandated that all Christians must offer sacrifices to the Roman gods or face execution. Convinced of his success, he even had a special medal struck that read, "The Christian religion is destroyed and the worship of the [Roman] gods restored." He was, to put it mildly, mistaken. Not only did Christianity survive, but it flourished, and within a few decades, it would become the empire’s official religion. Diocletian had unwittingly strengthened the very faith he tried to eliminate.

POLITICS Diocletian was a shrewd politician who fundamentally reshaped the Roman Empire’s administration. His establishment of the Tetrarchy allowed for more effective rule, as each emperor was responsible for a specific region. He also strengthened the imperial bureaucracy, introducing a more rigid hierarchy of government officials. His policies reinforced the authority of the emperor while also decentralizing power, a balance that ultimately proved difficult to maintain after his abdication.

SCANDAL Diocletian’s most controversial decision was his brutal persecution of Christians. While some Romans supported his efforts to restore traditional religious practices, many saw the extent of the crackdown as excessive. 

His economic reforms also sparked outrage—his Edict on Maximum Prices, which attempted to control inflation by fixing the prices of goods and wages, led to black market trading and economic instability. Some critics viewed his resignation in 305 as an act of cowardice rather than wisdom.

MILITARY RECORD Diocletian was a skilled military leader who successfully defended the empire from external threats. He secured the eastern frontier against the Sassanid Empire, strengthening Roman rule in the region. In the west, he repelled barbarian invasions and stabilized the empire’s borders. His military strategies were highly effective, ensuring that Rome remained dominant during his reign.

HEALTH AND PHYSICAL FITNESS By the time he retired in 305 AD, Diocletian’s health had begun to decline. Some historians suggest he suffered from a chronic illness, possibly arthritis or some form of digestive disorder. His decision to step down from power was unprecedented for a Roman emperor, but he recognized his physical limitations and chose a life of rest over the burdens of governance.

HOMES Diocletian's most famous residence was his grand palace in Split, Dalmatia (modern-day Croatia). This vast complex served as both a fortress and a luxurious retreat. After his abdication, he lived there in peaceful retirement, dedicating himself to gardening and agriculture. Today, Diocletian’s Palace remains one of the best-preserved Roman architectural sites and is a UNESCO World Heritage Site.

Illustration depicting Diocletian's Split palace in its original appearance by Ernest Hébrard.

TRAVEL As emperor, Diocletian traveled extensively across the Roman Empire, overseeing military campaigns, administrative reforms, and religious policies. He spent time in Rome, the eastern provinces, and along the Danube frontier. After abdicating, he settled in Dalmatia and lived out his days away from the political turmoil of the empire.

DEATH Diocletian died on December 3, 311 AD, in his palace in Split. The exact cause of his death remains unknown, though speculation suggests illness or even suicide, as he may have been disheartened by the collapse of his Tetrarchic system. Regardless of the circumstances, his legacy endured as one of the most influential emperors of late antiquity.

Diocletian was buried within his palace complex in Split, specifically in an octagonal mausoleum he had built for himself. The mausoleum was located at the eastern end of the palace, near his private apartments.

The mausoleum structure still stands today, but it has been significantly altered over the centuries. In the 7th century, it was converted into a Christian church dedicated to St. Domnius. Today, the former mausoleum serves as the Cathedral of Saint Domnius in Split. It remains one of the best-preserved ancient Roman buildings still standing

APPEARANCES IN MEDIA  Diocletian doesn’t have the same level of pop culture presence as, say, Julius Caesar or Nero—probably because he wasn’t assassinated in a dramatic fashion or known for playing the fiddle while Rome burned. However, he has made a few appearances in literature, film, and other media over the years.

Edward Gibbon’s The History of the Decline and Fall of the Roman Empire – Gibbon gives Diocletian a fair amount of attention, acknowledging his role in stabilizing the empire while also criticizing his persecution of Christians and his overly bureaucratic government.

Evelyn Waugh’s Helena – This novel, a fictionalized account of the life of Constantine’s mother, Saint Helena, portrays Diocletian as a formidable yet flawed ruler, particularly in his dealings with Christians.

1964 film Constantine and the Cross – Diocletian is portrayed as a powerful but ultimately doomed figure whose persecution of Christians sets the stage for Constantine’s rise.

Various history documentaries, including productions by the History Channel and the BBC, have covered Diocletian’s reign, particularly his persecution of Christians and his political reforms.

Diocletian appears as a faction leader during the Crisis of the Third Century in the video game Total War: Rome II – Empire Divided DLC. His historical role in restoring stability to the empire is a key gameplay element.

Diocletian (Opera by Gaetano Donizetti) – Though not his most famous work, Donizetti composed an opera titled Il Diluvio Universale that features Diocletian as a character.

Henry Purcell’s The Prophetess, or The History of Dioclesian – This 1690 semi-opera is loosely based on Diocletian’s story, though it takes creative liberties, as Baroque composers tended to do.

elf wasn’t in the show, his legacy (and impressive real estate choices) certainly made an impact.

ACHIEVEMENTS Established the Tetrarchy, a new system of government that briefly stabilized the empire.

Conducted major military reforms, strengthening the Roman army.

Initiated the Edict on Maximum Prices, an attempt to curb inflation (though it ultimately failed).

Constructed Diocletian’s Palace, one of the greatest architectural achievements of the Roman world.

Became the first Roman emperor to voluntarily abdicate, choosing retirement over continued rule.