The site chosen was that of a pre-existing Visigothic and Mozarabic church in the Campo de San Juan, situated outside the citadel.

[4] Due to its position outside the citadel, the church has a fortress-like appearance, with strong walls and bastions, and a sturdy square tower.

The portalis flanked by two Ionic columns and is surmounted by a niche with a statue of St. John the Baptist.

The portal of St. Blaise, on the southern side, is most likely the oldest one: it is flanked by two pilasters and features a small image of the saint to which it is entitled.

The cathedral's interior is in the late Gothic architectural style, and has a nave and two aisles, side chapels, a high altar (with a highly decorated Baroque retablo) and a choir with Plateresque stalls and a Baroque organ.