Originally the headboard showed a semicircular plan (like the Cathedral of Santiago) with a gallery (ambulatory) and to which three smaller chapels opened. The new headboard was replaced between 1606-1610, by the current rectangular plan, with a cradle vault lined with red, black and white stone boxes, ordered by Bishop D. Gonçalo de Morais. Around 1724-25, during the construction of the vacant seat, the four windows were opened to replace the narrow crevices and the granite pilasters were made with gilded capitals.

The primitive head of the Porto Cathedral had a very rich structure, it was not only made of charola, but it was formed by a double ambulatory, the upper gallery having a structural function, functioning as a supporting buttress of the forces transmitted to the walls by the weight of the stone vault. that covered the original Romanesque chancel.