The Cathedral complex is located on the highest point of the city, on a promontory that was initially used as a barracks for the Roman armies commanded by General Gnaeus Cornelius Scipio Calvus (3rd century BC). In the 1st century AD, this site was transformed into a sacred area presided over by the Temple of Augustus, which was probably transformed, during the Visigoth period (5th-6th century AD), into an episcopal complex with the Cathedral, baptistery and Bishop's palace. After the hiatus during the Islamic period, when no buildings are documented, the construction of the medieval cathedral began in 1171, thanks to the financial resources bequeathed by Archbishop Hug de Cervelló in his will. The cathedral was built on the remains of the religious site from the time of the Roman Empire.

The Cathedral, with a Latin cross design of 104 metres in length and a large cloister with marbled decoration and 295 capitals, became one of the most imposing Romanesque cathedrals in Christendom. In 1331 it was consecrated by the Archbishop and Patriarch of Alexandria, John of Aragon. Due to the Black Death that reached Tarragona in 1348, the façade was left unfinished. The chapels that open onto the side naves reveal how styles evolved from the Gothic to the Baroque period. Today, the Cathedral, metropolitan and primate, continues to be a spiritual and cultural beacon in the 21st century.