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By Ana Marendić, licensed tourist guide and art historian, Split, Croatia · Last updated: May 2026 · ~14 minute read
Diocletian's Palace in Split, Croatia is a Roman imperial residence built between approximately 295 and 305 AD as the retirement home of Emperor Diocletian, and it has been continuously inhabited ever since — making it unique among ancient monuments of its scale. When the nearby Roman capital of Salona was destroyed in the 7th century, refugees moved inside the palace walls and never left. Over 1,700 years, the imperial complex became a medieval city, then a modern one: today around 3,000 people live within its walls, the emperor's mausoleum is now a cathedral, and the Roman cellars are wine bars. This guide, written by a licensed Split tourist guide, traces the complete history of the palace — from its construction under one of Rome's most consequential emperors, through its transformation into a living city, to its UNESCO World Heritage status today.
There are ancient monuments, and then there are ancient monuments that people never left. Diocletian's Palace in Split is the second kind.
Built as a retirement complex for a Roman emperor in the late 3rd century AD, it has been continuously inhabited for 1,700 years. Today, around 3,000 people live within its walls, in apartments carved out of Roman rooms, medieval towers, and Renaissance additions. Restaurants occupy imperial cellars. A cathedral stands inside the emperor's mausoleum. It is a UNESCO World Heritage Site that is also, in the most literal sense, someone's home.
I am Ana Marendić, a licensed tourist guide in Split. This is the complete history of Diocletian's Palace — from its construction under one of Rome's most powerful emperors, through its transformation into a medieval city, to its rediscovery by Enlightenment architects and its current status as one of Europe's best-preserved ancient monuments.
To understand the palace, you have to understand the man who built it.
Gaius Aurelius Valerius Diocletianus was born around 244 AD in Salona — the Roman provincial capital located a few kilometres from the site of his future palace, near present-day Solin. His origins were humble: ancient sources suggest his father was either a scribe or a freed slave. He rose through the Roman military during a period of extraordinary instability — the Crisis of the Third Century — when the empire cycled through emperors with lethal speed, with over 50 claimants to the throne in a 50-year period, many of whom lasted only months before being assassinated or killed in battle.
Diocletian survived where others didn't. He was proclaimed emperor by his troops in 284 AD, after the mysterious death of Emperor Numerian. He then defeated and killed his rival Carinus the following year, becoming sole ruler of Rome. What followed was one of the most significant reigns in Roman history. For a complete biography, see our guide to Emperor Diocletian.
Recognising that the empire had become too large and too unstable for one man to govern alone, Diocletian invented something new: the Tetrarchy, or "rule of four."
In 285 AD, he appointed Maximian as co-emperor (Augustus) in the west. In 293 AD, he added two junior emperors (Caesars): Galerius in the east and Constantius Chlorus in the west. The empire was divided into administrative regions, each with its own court, military, and administration.
It was a radical restructuring — an acknowledgment that the traditional Roman model of a single all-powerful emperor had failed, and that pragmatic decentralisation was the path to stability. It worked, for a time. Diocletian's reign of 21 years was the longest since Augustus, and he ended it on his own terms — the first Roman emperor to voluntarily abdicate.
Diocletian's legacy is complicated by the Great Persecution, launched in 303 AD — one of the most severe and systematic campaigns against Christians in the empire's history. Churches were destroyed, scriptures confiscated, and Christians required to sacrifice to Roman gods or face imprisonment, torture, or execution.
The reasons are debated. Diocletian was deeply conservative in religious matters, committed to traditional Roman polytheism. His co-emperor Galerius is thought to have pushed for the more extreme measures. Whatever the causes, the historical irony is pointed: the man who persecuted Christians built the mausoleum that would eventually become Split's cathedral, dedicated to a Christian saint he had martyred.
Construction of the palace began around 295 AD and took approximately ten years. The site was chosen carefully: close to Diocletian's birthplace, facing the Adriatic Sea, positioned on a small peninsula that provided natural defensive advantages and a mild, sheltered climate.
The palace is enormous by any standard. It covers approximately 3 hectares (30,000 square metres) and is enclosed by walls up to 2 metres thick and 17–26 metres high. The southern wall, facing the sea, was more palatial in character — with a gallery of arched windows overlooking the Adriatic. The northern, eastern, and western walls were more military, reflecting the palace's dual character as both imperial residence and fortified garrison.
The overall plan is a modified Roman castrum — the standard layout of a Roman military camp. Two main roads, the Cardo (north-south) and Decumanus (east-west), intersect at the centre, dividing the complex into four quadrants:
It was, in essence, a small fortified city built to house one man and the apparatus required to serve him.
The stone came mostly from the island of Brač — the same white limestone later used in monuments across the Mediterranean. Granite columns were imported from Egypt, specifically from the quarries at Aswan. Marble came from Greece and elsewhere in the empire.
The labour force included both free workers and slaves. Construction at this scale required enormous logistical organisation — quarrying, shipping across the Mediterranean, skilled craftsmanship, and coordination across hundreds of workers over a decade.
The palace had four main gates, each oriented to a cardinal direction and each named for a metal in later tradition:
The Golden Gate was the most ceremonial, with two projecting towers, elaborate sculptural decoration (most now missing), and a passageway designed to impress arriving dignitaries. Diocletian would have entered through it for the first time in 305 AD.
On 1 May 305 AD, Diocletian did something no Roman emperor had ever done: he resigned.
In a ceremony at Nicomedia (in present-day Turkey), he removed his imperial purple robe and handed power to his Caesar Galerius. His co-emperor Maximian abdicated simultaneously in Milan. Diocletian retired to his completed palace in Split.
Ancient sources preserve a famous anecdote. When his former colleagues urged him to return to power during the subsequent political chaos, Diocletian reportedly replied that if they could see the cabbages he had planted with his own hands, they would never ask him to trade the peace of his garden for the pursuit of power.
He spent his final years gardening, receiving visitors, and watching his carefully designed Tetrarchy collapse into civil war from a safe distance. He died in the palace around 311–313 AD. His precise date and cause of death are unknown — some sources suggest natural causes, others suicide following the destruction of his political legacy.
The palace served its original imperial function for only about 170 years after Diocletian's death. It passed through various hands under the late Roman empire and was used as an administrative centre, a military base, and an occasional imperial residence. The transformation that made it a city came in the 7th century.
In the early 7th century, Avar and Slavic tribes swept through Dalmatia, destroying Salona — the regional capital that had stood for centuries a few kilometres away. The surviving population fled south and took refuge inside the massive walls of Diocletian's Palace.
This was the moment the palace became a city.
The refugees adapted the imperial structures to domestic use. The grand colonnade of the southern gallery became a street. The subterranean cellars, originally used for storage and as structural support for the imperial apartments above, were built over and gradually forgotten. The Peristyle — the great ceremonial courtyard — became the town square.
The most dramatic transformation was Diocletian's mausoleum. Originally an octagonal domed building where the emperor had intended to be worshipped after death as a deified ruler, it was converted into a Christian cathedral.
The conversion was probably an act of practical necessity — it was the largest and most structurally sound building available. But the symbolism was irresistible: the man who had persecuted Christians, his very tomb repurposed as a church, dedicated to Saint Domnius, a bishop Diocletian had martyred. A Christian bell tower was added beginning in the 13th century. The result, the Cathedral of Saint Domnius, is often described as the oldest Catholic cathedral in the world that remains in use within its original structure.
Through the medieval period, Split grew steadily within and around the palace walls. New buildings filled the spaces between Roman structures. Medieval towers rose on top of Roman foundations. The four main streets of the Roman layout remained in use, their basic geometry preserved by the buildings erected over them.
By the 13th century, Split had outgrown the palace walls and begun expanding beyond them. The area immediately outside the western gate became the commercial centre — today's People's Square (Narodni trg). But the palace remained the heart of the city, and the continuity of its use kept the Roman structure largely intact beneath later accretions. For the details most visitors miss, see our guide to 12 hidden details in Diocletian's Palace.
By the 18th century, the palace had been so thoroughly absorbed into the medieval city that its Roman origins were partially obscured. It took an architect from Scotland to bring it back to international attention.
In 1757, the Scottish architect Robert Adam arrived in Split with a team of draughtsmen and spent five weeks systematically measuring and documenting the palace. The result was Ruins of the Palace of the Emperor Diocletian at Spalatro in Dalmatia, published in London in 1764.
The book was a sensation. Adam's precise drawings revealed the palace's original Roman design beneath centuries of later construction, and his analysis of its architectural details directly influenced the development of Neoclassical architecture across Britain and Europe. The "Adam style" that shaped Georgian interior design owed a significant debt to his studies at Split.
The publication also established the palace as an object of serious scholarly interest. Subsequent researchers built on Adam's work, gradually reconstructing the original appearance of the complex from the physical evidence remaining within the inhabited city. Adam's survey remains one of the most important sources used in modern reconstructions of the palace — including the VR reconstruction used on the Time Walk tour today.
In 1979, the Historical Complex of Split with the Palace of Diocletian was inscribed on the UNESCO World Heritage List. The designation recognised the outstanding universal value of a monument that has been continuously inhabited since it was built — unique among ancient Roman structures of comparable scale.
The UNESCO status brought both resources and challenges. Restoration work has been ongoing since the 1970s, working carefully to preserve Roman, medieval, and later fabric together rather than attempting to "restore" the palace to any single historical moment. The result is what you see today: layers of history visible simultaneously, a palimpsest of 1,700 years of human habitation.
Approximately 3,000 people live within the palace walls. The Peristyle is a café terrace. The Cathedral of Saint Domnius — Diocletian's mausoleum — holds regular masses. Boutique hotels occupy Roman rooms. Restaurants fill the cellars. Art galleries and shops line the medieval streets.
The palace is what it has always been: a place where people live. That is what makes it different from every other ancient monument of comparable importance. It was never abandoned. It was never purely preserved. It was used, adapted, built over, and built within, continuously, for seventeen centuries.
The best way to understand this layering — to see the Roman palace beneath the medieval city, and to comprehend what Diocletian actually built here — is to see it as it was. The Time Walk VR walking tour does exactly that: an 80-minute guided experience through the palace using Meta Quest 3 headsets to reconstruct the original Roman structures on the actual sites where they stood.
You stand in the Peristyle and see the temple facade as Diocletian saw it. You walk through the Golden Gate and understand why it was designed to impress. You see the throne room as a throne room, not as the apartment block it later became.
80 minutes · €19 · Small groups · Rated ★ 5.0 across 170+ verified reviews · Available in English
Diocletian's Palace is approximately 1,720 years old. Construction began around 295 AD and was completed around 305 AD, when Emperor Diocletian moved in. It has been continuously inhabited ever since, making it one of the oldest continuously occupied structures of its scale in the world.
Diocletian's Palace was built by the Roman Emperor Diocletian as his retirement residence. Construction took approximately ten years (c. 295–305 AD) and used white limestone from the island of Brač, granite columns imported from Egypt, and marble from Greece. The labour force included both free Roman workers and slaves.
Diocletian's Palace was built between approximately 295 and 305 AD. The emperor moved into the completed palace on or shortly after his abdication on 1 May 305 AD — the first Roman emperor ever to voluntarily resign.
Diocletian built his palace near his birthplace of Salona, on a sheltered peninsula on the Dalmatian coast that offered a mild climate, natural defensive advantages, and proximity to home. The site, then called Spalatum, faced south over the Adriatic and was protected from harsh weather by surrounding hills. Diocletian was a Dalmatian by birth, and the location allowed him to retire close to where he had grown up.
Yes. Approximately 3,000 people live inside the walls of Diocletian's Palace today, in apartments built into Roman, medieval, and Renaissance structures. The palace is the living historic centre of the modern city of Split. This continuous habitation, unbroken since the 7th century, is what makes the palace unique among Roman monuments of its scale.
Today Diocletian's Palace functions as the historic centre of Split — a mix of private residences, the Cathedral of Saint Domnius, restaurants, wine bars, boutique hotels, shops, galleries, and cafés. The Peristyle is a public square and café terrace; the Roman cellars host markets, exhibitions, and restaurants; the cathedral holds regular Catholic masses. It is simultaneously a UNESCO World Heritage Site and an ordinary working neighbourhood.
Diocletian's Palace covers approximately 30,000 square metres (3 hectares), enclosed by walls 17 to 26 metres high and up to 2 metres thick. It was laid out as a rectangle measuring roughly 215 by 180 metres, following the plan of a Roman military camp, with four gates and two main intersecting streets.
After Diocletian's death around 311–313 AD, the palace continued as a late Roman administrative centre and occasional imperial residence for about 170 years. Its transformation into a city came in the 7th century, when refugees from the destroyed nearby capital of Salona settled inside its walls and never left. They adapted the Roman structures into homes, converted the mausoleum into a cathedral, and turned the imperial courtyard into a town square — beginning the continuous habitation that survives today.
Diocletian's Palace is important as one of the best-preserved Roman imperial palaces in the world and the only one to have been continuously inhabited for 1,700 years. It is a uniquely complete example of late Roman imperial architecture, it preserves the original layout of a Roman residence at full scale, and its 18th-century survey by Robert Adam directly influenced Neoclassical architecture across Europe. It has been a UNESCO World Heritage Site since 1979.
Yes — it is one of the most remarkable historical sites in Europe and the principal reason most visitors come to Split. Unlike most Roman ruins, the palace is a living, walkable, free-to-enter city centre rather than a fenced-off archaeological site. To understand what you are seeing, a guided tour is strongly recommended; a VR-enhanced walking tour adds a reconstruction of the original Roman palace on top of the standing structure.
Ana Marendić is a licensed tourist guide (turistički vodič) registered with the Croatian Ministry of Tourism and Sport. She conducts walking tours of Diocletian's Palace and Split's historic centre as the resident guide for Time Walk, a VR-enhanced walking tour of the palace. She is based in Split, Croatia.
This history draws on the author's professional guiding experience inside Diocletian's Palace, supplemented by primary and secondary historical sources. The account of Diocletian's reign and the Tetrarchy follows standard scholarship including Williams (1985) and Barnes (1982). The architectural description of the palace follows Wilkes (1986) and the Marasović surveys (1968 onward). Robert Adam's 1764 publication is used directly for the 18th-century rediscovery. The continuous-habitation narrative and UNESCO designation follow the UNESCO World Heritage nomination dossier for the historical complex of Split. Where dates are uncertain in the historical record — particularly Diocletian's birth and death — the article uses the ranges accepted by current scholarship.
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