Building on the church began in the last quarter of the 12^th century, in a late-Romanesque style, in the heart of the Frankish quarter at the foot of the Major castle. It is here that the Navarrese monarchs Juan and Catalina de Albret, the Emperor Carlos V and King Felipe II, all swore their allegiance to the “fuero” charters and privileges of the city.

With an irregular ground plan due to its confined setting, it is made up of three naves with a Romanesque chancel containing three apses. The naves on either side present rib vaults (15^th century) while the main nave boasts a half barrel vault with lunettes (17^th century).

The portico (circa 1230) presents a lobed arch of Arabic influence and rich ornamentation. The tower stands at the foot of the nave and lends it the air of a fortress. The entrance steps, built in 1966, are the work of the architect Francisco Pons-Sorolla.

The cloister (late 12^th century) houses a rich collection of sculptures. It only conserves the north and west galleries, as the other two were destroyed in 1572 when the castle was set upon. Its twin columns feature capitals presenting historical themes, vegetable motifs and fantastical creatures.

In its interior, of particular note is Saint Andrew’s chapel (1596). It houses the relic of the apostle Saint Andrew, the patron saint of the city, who, according to tradition, arrived at the city with the helping hand of the Bishop of Patrás in 1270.

Of particular interest among the images that are preserved, are two Romanesque carvings of a crucified Christ and the Virgin of Bethlehem (13^th century), a crucifix (14^th century) and a Baroque carving of Saint Peter (1687).

The church was restored between 2009 and 2012.