Diocletian's Palace

Put your hand on the nearest wall. The stone is pale, almost white, and smooth where millions of palms and shoulders have brushed past it. Listen for a moment. You may hear coffee cups, a scooter in a narrow lane, laundry flapping above your head. You are standing inside a Roman emperor's retirement home. Today it is also a living neighbourhood, and people still sleep, cook and argue behind these walls.

The man who built it was Diocletian. He was born in this region of Dalmatia, a soldier of humble origins who rose to rule the Roman Empire in the late third century. He reorganised the empire, divided power among several co-rulers, and reshaped its administration and taxes. Then, in the year 305, he did something almost no Roman emperor ever did. He stepped down voluntarily, and he came home to this bay on the Adriatic.

The palace was built for that retirement, around the turn of the fourth century. It was not a single mansion. It was closer to a fortified town, a rectangle of walls and towers with a grid of streets inside. The builders used limestone from the nearby island of Brač, and Diocletian added imported marble and granite. Part of the plan followed a Roman army camp. Part of it was a luxury villa facing the sea.

Notice the four gates. Romans did not name them this way, but later generations did, and the names stuck. The Golden Gate opens to the north, toward the old road to Salona, the Roman capital of the province. The Silver Gate faces east. The Iron Gate faces west. And the Bronze Gate, small and plain, opens to the south. In Diocletian's day, the sea came almost up to that southern wall.

At the centre of everything is the Peristyle, the ceremonial courtyard. A peristyle is simply a space surrounded by columns. Here, tall granite columns carry arches on both sides, and wide stone steps lead up toward a raised porch. This was where the emperor appeared before his subjects, treated almost as a living god. Today the steps are covered in cushions, and people sit with coffee or wine in the same spot.

Look for the black sphinx near the columns. Diocletian brought several sphinxes from Egypt, which were already ancient when they arrived. Most were damaged or lost over the centuries, partly because later Christians saw them as pagan. One survives here, headless no longer but worn and weathered, gazing across the courtyard. It is older than the palace itself by well over a thousand years. Most visitors walk right past it.

Now turn to the octagonal building with the tall bell tower. This was Diocletian's mausoleum, the tomb he prepared for himself. Here is the first great irony of this place. Diocletian led one of the harshest persecutions of Christians in Roman history. Among the people executed under his rule was Domnius, a bishop of Salona. Centuries later, this tomb became a cathedral dedicated to Saint Domnius. The persecutor's resting place now honours one of his victims. What happened to the emperor's body is not known for certain.

The bell tower rises above the courtyard in the Romanesque style, a medieval style of round arches and heavy masonry. It was built over a long period, starting in the Middle Ages, and was heavily restored in the early twentieth century. If you have the energy, the climb rewards you with a view over red roofs, the harbour, and the islands floating on the horizon. The stairs are steep and open in places, so take your time.

So how did a palace become a town? In the seventh century, Salona was attacked and largely abandoned. Its people fled to the coast and moved inside Diocletian's walls, which were strong and still standing. They built houses into the arches, churches into the temples, and shops into the corridors. Over the following centuries, Venetian windows, Renaissance doorways and Baroque balconies were added. Every wall you see carries layers from different ages, often in a single facade.

South of the Peristyle is the Vestibule, a round, domed hall where visitors once waited to meet the emperor. The top of the dome is open to the sky, so a circle of light falls onto the floor. The acoustics are remarkable. On many days you will hear klapa singers here. Klapa is a Dalmatian tradition of unaccompanied harmony singing, usually by small groups of men. The sound fills the stone room and stays with you.

Below your feet is the second surprise. Beneath the emperor's living quarters lie huge vaulted cellars, the substructures that supported the floors above. For centuries, residents used them for storage and threw rubbish into them, which filled them up. That rubbish protected them. When they were excavated, they turned out to preserve the layout of the lost rooms above almost perfectly. Television fans may recognise them, because scenes from Game of Thrones were filmed down there.

West of the old town, outside the Golden Gate, a giant bronze bishop raises his hand. This is Gregory of Nin, a medieval churchman remembered for defending the use of the local language in church services. The sculpture is by Ivan Meštrović, Croatia's most celebrated twentieth-century sculptor. Look at the big toe. It shines gold, rubbed bright by people who touch it for luck. Locals say it brings you back to Split.

There is one more story about Diocletian himself. According to an ancient account, when former colleagues begged him to return to power, he refused. He told them that if they could see the cabbages he grew with his own hands, they would never ask. Whether he said exactly those words, nobody can prove. But the image fits this place.

Before you leave, stand still on the smooth paving and look up. Washing lines cross above Roman arches. A satellite dish sits beside a medieval window. Somewhere a door opens, and someone steps out with their shopping. This is not a ruin. It is a palace that people simply never stopped using. As you walk out toward the sea, notice how easily the old walls become the city.