The Basilica of Saint Saturno is one of the most antic buildings in Sardinia.  It rises in the Square of St. Cosimo in Cagliari in a spacious area where once Roman and Christian Necropolises were constructed.
The church is dedicated to St. Saturn, the city's patron saint, a young Christian martyred in 304 A.D. in the same place.  The original foundations of the church come from the V Century and had a cross plan.  Nowadays, there is only a big dome and part of the apse that remain from this period.  In the following century, the monastery was added to the church.  Between 1089 and 1119, the original structure of the building was modified and enlarged by the Vittorini Monks from Marseilles; they received the complex from the Judge of Cagliari.  They completed the church's east wing with three naves covered by a barrel roof.  After the abandonment of the church by Vittorini, it survived periods of decline and the renaissance.  In 1324, during the Aragonese siege, the monastery suffered a lot of damages and successively fell into decay.  Fortunately, the basilica's destiny was favourable and it was reconstructed in the XV Century.  Some of its original stones were used to build the Castle on the hill of Saint Michele (Castello del colle di San Michele).
In the XVII Century, during the search for the "saintly bodies" of the martyred Christians, what are presumed to be the relics of St. Saturn, were uncovered in the church.  Today, all of the relics are conserved in the Cathedral of Cagliari in Piazza Palazzo.
In 1714, the Basilica was entrusted to the Corporazione of Medici and Speziali who dedicated it to the Saints Cosma and Damian.
During the bombardments in 1943, the Basilica suffered very serious damage.  However, it was restored between 1948 and 1952.
Recently new restoration has been initiated and the Basilica is closed to the public.