The cathedral was built on the site of several former cathedrals, including 6th, 10th and 11th century buildings, and their 12th century successor in the Romanesque style, which was largely destroyed in the earthquake of 1667. The Senate of Dubrovnik appealed to the architect Andrea Bufalini who sent a model for the new church. Several other Italian architects including Francesco Cortese (present from 1669 until his death in 1670), Paolo Andreotti (present 1671-1674), Pier Antonio Bazzi (present 1677-78), and Tommaso Maria Napoli of Palermo (present 1689 - 1700), all working with local and imported stonemasons, completed the Cathedral over the next three decades. Napoli made several crucial changes to the original plans including the use of a cross vault and the opening of large thermal windows at the upper level. This gives the whole interior a lighter and brighter feel. The style of the Cathedral is in keeping with the esthetics of Roman Baroque architecture as practiced by Bernini, Carlo Fontana and their 17th century contemporaries. The building features three high naves, three apses and a grand Baroque dome. The main altar holds a polyptych by Titian, portraying a version of the Assumption of the Virgin. This painting probably dates from 1552; the side altars hold paintings of later centuries.
The Cathedral treasury (Riznica Katedrale) holds 200 reliquaries holding relics from the 11th to 18th centuries; chiefly, the gold-plated arm, leg and skull of Saint Blaise and a relic of the True Cross.
The cathedral was damaged by at least one shell during the Siege of Dubrovnik. The damage has since been repaired.