The Cathedral of Saint Domnius (Katedrala svetog Duje) stands inside Diocletian's Palace in Split, and it was built as the Roman emperor Diocletian's own mausoleum around AD 305. It is often described as the oldest Catholic cathedral still in use in its original building. The twist: it is dedicated to Domnius, a bishop who was executed during Diocletian's persecution of Christians.
St Domnius Cathedral at a glance
- Where: on the east side of the Peristyle, the colonnaded square at the centre of Diocletian's Palace in Split's old town.
- Built: as Diocletian's mausoleum in the early 4th century; turned into a church in the 7th century. The bell tower was built between the 13th and 16th centuries and largely rebuilt around 1890–1908.
- What it is today: the cathedral of the Archdiocese of Split-Makarska and part of the Historic Complex of Split with the Palace of Diocletian, a UNESCO World Heritage Site since 1979.
- Time needed: about 30 minutes for the cathedral, 30–45 minutes if you add the bell tower, the crypt and the treasury.
From pagan mausoleum to Christian cathedral
Diocletian, who ruled from 284 to 305, built his palace on the coast near his home region and had his tomb placed at its heart: an octagonal building outside, round inside, ringed by a colonnade. In 304, during the last great persecution of Christians, Domnius, the bishop of nearby Salona, was beheaded there. When Salona was abandoned in the 7th century, its refugees settled inside the palace walls, threw out the emperor and turned his mausoleum into their church. Diocletian's sarcophagus disappeared, and the relics of Domnius were brought in instead.
Over the following centuries the Romanesque and Gothic town added to it. The carved wooden doors date from 1214, the choir stalls from the 13th century, and the two side altars from the 15th century. The bell tower was begun in the Romanesque period and finished in the 16th century; the restoration of around 1890–1908 replaced much of its stonework, removing many of the original sculptures. The tower reopened to visitors in 2020 after two years of work on its stairs and stone.
What to look for
- The main doors by Andrija Buvina, carved in walnut in 1214, with 28 scenes from the life of Christ, 14 on each wing.
- The Roman frieze around the base of the dome, with hunting cupids, masks and two medallion portraits usually identified as Diocletian and his wife Prisca. The emperor is still looking down on his former tomb.
- The altar of Saint Domnius by Bonino da Milano (1427) and the altar of Saint Anastasius by Juraj Dalmatinac (1448), on either side of the nave.
- The 13th-century hexagonal stone pulpit on slender columns, to the left of the entrance.
- The bell tower, 57 metres tall. The climb up narrow steps, the last part on open metal stairs, gives a view over the red roofs, the harbour and the islands.
- The black granite sphinx on the Peristyle in front of the cathedral, one of several Diocletian brought from Egypt.
The emperor and the saint
Few buildings carry a stronger irony. Diocletian launched the harshest persecution the early Church faced, and Domnius was one of its victims. Within a few centuries the persecutor's tomb had become the martyr's cathedral, and Split's patron saint is honoured here every year on 7 May, the Feast of Saint Domnius (Sudamja), the city's biggest festival.
Tips for your visit
- Cover shoulders and knees inside the cathedral, and save the bell tower climb for when you have good shoes and a few spare minutes.
- Come early in the morning or in the late afternoon: cruise groups fill the Peristyle around the middle of the day.
- For the best view of the tower, stand on the Peristyle steps opposite the cathedral or look up from the Riva promenade.
- Walk into the round Vestibule just south of the Peristyle: it was the entrance hall to the emperor's apartments and has a remarkable echo.
Nearby
- Peristyle: the colonnaded square in front of the cathedral, once the ceremonial courtyard of Diocletian's Palace.
- Temple of Jupiter: a small Roman temple a few steps west of the Peristyle, later turned into the cathedral's baptistery.
- Golden Gate and Gregory of Nin: the palace's northern gate, and outside it Ivan Meštrović's giant statue of the medieval bishop, whose big toe visitors rub for luck.
- Riva: the palm-lined seafront promenade along the southern wall of the palace, a short walk away.
See Split with World City Trail
Our Split scavenger hunt turns the old town into a game you play on your phone. The route links 10 stops and takes around 2 hours, with about 20 minutes of walking. It includes the Golden Gate of Diocletian's Palace, the statue of Gregory of Nin and the Croatian National Theatre.
If you prefer a different format, there is also a self-guided walking tour and an outdoor escape game in Split.
Play the Split scavenger hunt →
Take the self-guided walking tour of Split →
Play the outdoor escape game in Split →
Facts checked in October 2026.