"It is a former collegiate church also called Saint-Paul-Serge basilica.
A first building burned down in the 5th century was rebuilt. This pre-Romanesque church was rebuilt around 1180 to the dimensions of the current church with a nave, a non-projecting transept and a choir. The latter, destroyed at the beginning of the 12th century, was rebuilt in 1224 at the instigation of Abbot Robaldus (or Robaldo) who later became Bishop of Pavia in 1232; during this reconstruction the transept, the nave and the aisles were taken over and transformed. The tomb of Saint Paul, the first bishop of Narbonne, who according to tradition would be the proconsul Sergius Paulus, was transferred in 1244 to the choir of the church. The works ended in 1265.
After a fire in the roof of the nave which occurred in 1368, the vaults and the porch bell tower were redone. The two western spans were rebuilt from 1432 to 1458. In the 16th century, six pillars of the nave were reinforced by powerful circular blocks.
At the very beginning of the 16th century, we thought of erecting a bell tower on the western porch. However, this bell tower has remained unfinished since 1508, when the new ramparts were attached to the facade of the church.
The current composition is the result of numerous works and various restorations, which began in the 15th century with modifications to the nave. Around 1534, six pillars of the nave were surrounded by a circular massif, and the last chapel on the south aisle was remodeled around 1534. In 1751 the bell tower was consolidated and raised by a floor. But the most important restoration campaign undertaken in Saint-Paul is the fruit of the work of Henri Nodet, who redid the large bays of the transept braces and restored the balustrades in the galleries of the ambulatory and the choir in the 20th century. In addition, it should be noted that Pope Pius XII erected the church as a minor basilica in 1953."