The Cathedral of Saint Domnius in Split is 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 was 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 as the Mausoleum of Diocletian, is the second oldest structure used by any Christian Cathedral.
The main part is Emperor Diocletian's mausoleum, which dates from the end of the 3rd century. The mausoleum was built like the rest of the palace with white local limestone and marble of high quality, most of which was from marble quarries on the island of Brač, with tuff taken from the nearby river Jadro beds, and with brick made in Salonitan and other factories.
Later, in the 17th century a choir was added to the eastern side of the mausoleum. For that purpose the eastern wall of the mausoleum was torn down in order to unify the two chambers.
The Bell Tower was constructed in the year 1100 AD, in the Romanesque style. Extensive rebuilding in 1908 radically changed the Bell Tower, and many of the original Romanesque sculptures were removed.
One of the best examples of Romanesque sculpture in Croatia, are the wooden doors on Cathedral of St. Domnius. They were made by the medieval Croatian sculptor and painter Andrija Buvina around 1214. Two wings of the Buvina wooden door contains 14 scenes from the life of Jesus Christ, separated by rich ornaments in wood.
On the first floor of the sacristy is the cathedral treasury, which contains relics of Saint Domnius, which were brought to the cathedral after his death. Other treasures include sacral art works, like the Romanesque The Madonna and Child panel painting from the 13th century, objects like chalices and reliquaries by goldsmiths from the 13th to the 19th century, and mass vestments from the 14th till 19th century. It also contains famous books like the Book of gospels (Splitski Evandelistar) from the 6th century, the Supetar cartulary (Kartularium from Sumpetar) from the 11th century, and the Historia Salonitana (The History of the people of Salona) by Thomas the Archdeacon from Split in the 13th century.
References:The historic city of Trogir is situated on a small island between the Croatian mainland and the island of Čiovo. Since 1997, it has been included in the UNESCO list of World Heritage Sites for its Venetian architecture.
Trogir has 2300 years of continuous urban tradition. Its culture was created under the influence of the ancient Greeks, and then the Romans, and Venetians. Trogir has a high concentration of palaces, churches, and towers, as well as a fortress on a small island. The orthogonal street plan of this island settlement dates back to the Hellenistic period and it was embellished by successive rulers with many fine public and domestic buildings and fortifications. Its beautiful Romanesque churches are complemented by the outstanding Renaissance and Baroque buildings from the Venetian period.
Trogir is the best-preserved Romanesque-Gothic complex not only in the Adriatic, but in all of Central Europe. Trogir's medieval core, surrounded by walls, comprises a preserved castle and tower and a series of dwellings and palaces from the Romanesque, Gothic, Renaissance and Baroque periods. Trogir's grandest building is the church of St. Lawrence, whose main west portal is a masterpiece by Radovan, and the most significant work of the Romanesque-Gothic style in Croatia.