Cathedral of Saint Domnius

The Cathedral of Saint Domnius (Croatian: Katedrala Svetog Duje), known locally as the Sveti Dujam or colloquially Sveti Duje, is the Catholic cathedral in Split, Croatia. The cathedral is the seat of the Archdiocese of Split-Makarska, currently headed by Archbishop Zdenko Križić. The Cathedral of St. Domnius is a complex of a church, formed from an Imperial Roman mausoleum, with a bell tower; strictly the church is dedicated to the Virgin Mary, and the bell tower to Saint Domnius. Together they form the Cathedral of St. Domnius. The Cathedral of Saint Domnius, consecrated at the turn of the 7th century AD, is regarded as the oldest Catholic cathedral in the world that remains in use in its original structure, without near-complete renovation at a later date (though the bell tower dates from the 12th century). The structure itself, built in AD 305 inside of UNESCO World Heritage Site Diocletian's Palace as the Mausoleum of Diocletian, is the second oldest structure used by any Christian Cathedral. It's one of the most recognisable landmarks of Split.

The cathedral was named after Saint Domnius (Saint Dujam, or Saint Domnius) patron saint of Split, who was a 3rd-century Bishop of Salona. Salona was a large Roman city serving as capital of the Province of Dalmatia. Today it is located near the city of Solin in Croatia. Saint Domnius was martyred with seven other Christians in the persecutions of the Emperor Diocletian. He was born in Antioch, in modern-day Turkey, and beheaded in 304 at Salona.

When the Avars and Slavs destroyed Salona in the 7th century, part of the population fled to the nearby islands. After some time, a portion of these refugees returned to the mainland and settled within the abandoned imperial palace of Diocletian's Palace. They converted the emperor’s mausoleum into a Christian church, destroying the pagan idols as well as the sarcophagus in which the emperor had once been buried. From the ruined basilicas of Salona, they then transferred the relics of Christian martyrs whom Diocletian himself had ordered to be executed: Saint Domnius, the first bishop of Salona, and Saint Anastasius of Aquileia, a humble worker. According to the tradition recorded by the 13th-century Split chronicler Thomas the Archdeacon, these events took place during the tenure of Split’s first archbishop, John of Ravenna. Among Europe’s cathedrals, the cathedral in Split is unique in that it occupies the oldest structure ever used as a cathedral: the mausoleum of the Roman emperor Diocletian. At the close of the second millennium, this building stands as a powerful reconciliation of pagan antiquity, Christian medieval tradition, and modern heritage. The mausoleum of an emperor once known for persecuting Christians was transformed in the mid-7th century into a cathedral, where altars with the relics of Saint Domnius and Saint Anastasius—martyrs executed in nearby Salona—were placed in positions of honor.

The mausoleum’s exterior octagon was originally surrounded by a colonnaded porch (a peripteral ambulatory) supported by 24 columns. Inside, the space is circular, articulated by four semicircular and four rectangular niches. At its center once stood Diocletian’s sarcophagus, later destroyed. Above the niches rise eight Corinthian columns of red granite, topped by another ring of eight smaller columns. A continuous frieze runs around the interior, carved in relief with hunting Erotes, theatrical masks, and human heads. Particularly intriguing are two ribboned medallions, which archaeologists and local Split tradition identify as portraits of Emperor Diocletian and his wife Prisca. The dome is an architectural highlight: built with fan-shaped brickwork in its lower sections and circular brick courses in its upper third. Like the dome of t

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