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).

On the intersection of two main roads, cardo and decumanus, there is a monumental court Peristyle, from which the only access to Cathedral of St. Domnius is to the east.

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.

Extensive rebuilding in 1908 radically changed the Bell Tower, and many of the original Romanesque sculptures were removed.

Two wings of the Buvina wooden door contains 14 scenes from the life of Jesus Christ, separated by rich ornaments in wood.