– 718), a disciple of someone close to Mohammed, built the main mosque of Saraqusta al Baida, Zaragoza la Blanca, according to Al-Ḥumaydī (1029–1095).

The new church, with a basilical layout consisting of a transept and three naves ending in apses, constructed of stone, owed much stylistically to the Cathedral of Jaca, from which it took various elements.

From this era the lower part of two of the apses is still preserved, with small windows between inscribed capitals depicted, adorned with so-called "checkered jaqués" on the outside, and, inside, a set of sculptures that at present are hidden behind the main altarpiece.

The ceremony included four parts: investiture of weapons, unction with holy oil, placing of the crown and the royal insignia, and oath of the fueros (statutes) and liberties of the Kingdom of Aragon.

In 1318 Pope John XXII created the archbishopric of Zaragoza, making it independent of the see of Tarragona, and with that the building became a metropolitan cathedral.

In 1346, a Mudéjar dome was started to provide light at the altar, with the participation of the masters Juan de Barbastro and Domingo Serrano.

The work was finished in 1376, when Don Lope Fernández de Luna was already archbishop, creating a spacious, well-lit Gothic cathedral.

In 1360, during the archbishopric of Don Lope Fernández de Luna, the main facade was renovated and the so-called Parroquieta was built, all in the Mudéjar style.

The construction, elegantly carried out in Gothic-Mudéjar style, is a unique example of the work of the Aragonese masters and the Seville builders, who covered the exterior wall with geometric drawings made of smooth brick and glazed ceramic.

Dalmau Mur concentrated on beautifying the interior of the building, taking charge of, besides the main altarpiece, the chorus and other smaller constructions.

On September 14, 1485, Pedro de Arbués, the canon and head Inquisitor of Aragón, was assassinated in the cathedral as he was praying while wearing a helmet and chain mail.

As a consequence, there arose a popular movement against the Jews; "nine were finally executed in persona, in addition to two suicides, thirteen burnings at the stake, and four punished for complicity" according to the account of Jerónimo Zurita.

La Seo was built on the site of the ancient Roman forum of Augustus and of the main mosque of the Moorish city of Saraqusta, elements of whose minaret form part of the current tower.