The Seo del Salvador in its Epiphany is one of the two metropolitan cathedrals of the archdiocese of Zaragoza, together with the cathedral-basilica of Nuestra Señora del Pilar. In the diocese it is usually called simply La Seo, as it is the first cathedral as opposed to the lesser basilica, "El Pilar". It is built on the site of the ancient Roman forum of Caesaraugusta and the great mosque of Saraqusta, whose minaret still remains in the current tower. The building was begun in the 12th century in the Romanesque style, integrated into the aljama mosque, and underwent many alterations and extensions until 1704, when the Baroque spire was placed at the top of the tower. However, it was not until 1788 that the statues representing the cardinal virtues were placed on the new tower of the Cathedral, on the body of the clock tower.

In its current state, the Seo is a church with five naves and six bays covered by ribbed vaults of the same height, which gives the building the appearance of a church with a quadrangular hall plan. At the chancel there are two apses (of the original five) and, on the epistle side, the sacristy was placed on top of two of the missing apses. At the end of the Gospel side, the "Parroquieta" was built to house the tomb of Lope de Luna.

The structure of the naves is supported by buttresses characteristic of the late Gothic style (and not by flying buttresses as is usual in the classical Gothic style) which are closed by walls forming interior chapels. The transept (which does not stand out on the ground plan) is covered by a Mudejar-style dome.

The main construction material is brick, which is common in Aragonese architecture. The exterior of the cathedral as a whole does not reflect the internal structure, due to the enclosure with walls of several surrounding spaces as outbuildings or residences of the members of the chapter.

The main entrance is on the western side, where a classicist Baroque façade was erected in the second half of the 18th century to replace the 14th-century Mudejar portal, which is located behind the current doorway. The Baroque bell tower attached to the west wall and the Dean's house and arch, which connects the cathedral with an exterior building across the street, complete the cathedral complex.