Construction of the Seu Vella began in 1203 under the direction of the master builder Pere de Coma. According to historians, it was built on top of a former Muslim mosque. The temple, which was dedicated to Santa Maria, was consecrated for worship in 1278, but building work continued interrupted and in the 14th century the cloister was finally completed. During the 14th century, construction began on the bell tower and continued until 1431.


The temple was originally designed as a three-aisled basilica with a Latin cross layout. Inside, the most outstanding features include the sculptures that decorate its naves and which reveal the influence of the workshops of Tuscany, Toulouse and Provence whose craftsmen worked on the building throughout the 13th century. There are also remains of murals belonging to the Gothic period.


Access to the architectural complex is through the Porta dels Fillols , Fillols door), which is located in the south side of the building. The five monumental doors on this south wall provide a fine example of the sculpture and architecture associated with the late Romanesque period and known as the Escola de Lleida (the Lleida School).


Work on the west door, or Apostles' Door, which provides easy access to the cloister from the exterior, began in the 14th century and was completed during the 15th century. This monumental Gothic-style door was originally presided over by the Mare de Déu del Blau (Virgin in Blue).