In the hill of Bonaria, the tombs of the Roman necropolis and of the first Christian community of Cagliari were excavated. To the south of the basilica stands the sanctuary built in 1324-25, the oldest Gothic-Catalan architecture in Sardinia.
At the end of the 17th century, Father Bernardo de Cariñena, mercenary of the convent of Bonaria, became archbishop of Cagliari. It was he who wanted the construction of a new church, to be added to the ancient fourteenth-century sanctuary. Work began in 1704 but did not go beyond the preliminary stages.
When Sardinia passed to the Duchy of Savoy, a new project was entrusted to the Piedmontese military engineer Antonio Felice De Vincenti. He also executed a valuable wooden model, which still exists today, considered the earliest and most organic testimony of Baroque in Sardinia. De Vincenti blends Piedmontese, in particular Guarinian, and Spanish elements, learned both in Sicily and in Sardinia. The project included a three-aisle structure, an unpronounced transept, domes over the presbytery and at the intersection with the transept, an entrance pronaos. Although never built, it was an example for the subsequent island architecture.
In 1742, the pronaos was built. Between 1764 and 1765, the Cagliari marmoraro Squinardi created the twin columns and the capitals that mark the aisle. The work was then completed by the carpenters Denergry and Dejoannis. In 1778, another Piedmontese engineer, Giuseppe Viana, made significant changes to the project, which were also never carried out.
Due to lack of funds and because of the opposition of the Savoy government, the works were permanently suspended in 1804; in 1866 the convent and the area of the erected church were confiscated by the City of Cagliari and the rest passed to the State State Property.
Only on the occasion of the works that disrupted the structure of the sanctuary, between 1869 and 1875, did the project to complete the church resume. In 1907, Pope Pius X proclaimed the Virgin of Bonaria the Patroness Maxima of Sardinia; the event certainly had to accelerate the reopening of a construction site now invaded by vegetation and with dangerous structures due to its long exposure to the elements. Work resumed in 1910 under the direction of engineer Simonetti, who decided to make the covers of the naves and the dome at the intersection with the transept in reinforced concrete; this is one of the first examples in Sardinia of the use of the new material, whose design and execution was carried out by the Porcheddu company in Turin. The church was consecrated, even if not completely completed, in 1926, and was given the title of Minor Basilica by Pius XI.
Of cold classicist forms, it has a Latin cross structure. The façade is divided into two orders: the lower one, with three frames framed by pairs of pilasters, leads into the entrance pronaos, divided into three bays; in the upper one, the lodge of blessings surmounted by a tympanum with the coat of arms of the mercenaries opens.
The interior, with three naves and a wide transept, has ten chapels, four on each side in the aisles and two in the transept, on the sides of the presbytery. The central aisle has a barrel vault punctuated by sub-arches, the side aisles have vaulted vaults surmounted by octagonal domes. At the intersection with the transept, there is a dome on an octagonal drum, concluded with a lantern.
The bombing of 1943 caused the fall of the golden stuccos of the vaults and the dome, the frames and the painted plaster. The first restoration works, carried out by the Civil Engineers immediately after the war, were followed, from 1958, by those that gave the building its current appearance, directed by the Perugian architect Gina Baldracchini. The degradation of reinforced concrete structures, caused by humidity and brackish air, required further direct restoration work, between 1983 and 1998, by the architects Jolao Farci and Marco Atzeni.

History of studies
The church is the subject of a brief summary in Salvatore Naitza's volume on late seventeenth-century and purist architecture (1992).

Bibliography
The Restored Sanctuary of Our Lady of Bonaria, Cagliari, Società Poligra Sarda, 1960;
A. Cavallari Murat, “Giuseppe Viana, Savoy architect in Sardinia”, in Technical Review of the Engineering and Architects Company in Turin, n.s., 14, n. 12, December 1960;
A. Cavallari Murat, “Investigations into the expansion of Piedmontese eighteenth-century architecture in Sardinia”, in Bulletin of the Study Center for the History of Architecture, 17, 1961; P. Leo-G.
Melchionna, Sanctuary of Our Lady of Bonaria, Cagliari, Sardinian Polygraphic Society, 1970;
M. Pintus, “Sanctuary, Basilica and Convent of Our Lady of Bonaria”, historic districts in Cagliari. Villanova, Cinisello Balsamo, Silvana, 1991;
S. Naitza, Architecture from the late 17th century to purist classicism. Nuoro, Ilisso, 1992, sheet 15;
A. Sanna, First applications of reinforced concrete in Sardinia. The Cagliari works of engineer G.A. Porcheddu, Cagliari, CUEC/DIARCH, 2003;
I. Farci, “Ligurian and Lombard marble masters active in Sardinia from the mid-eighteenth century to the first decades of the nineteenth century”, in Quaderni oristanesi, 51-52, 2004.