Errenteria Church, as we know it today, is a building dating from the 16th Century, when the former parish construction (about which we know practically nothing) was renovated and enlarged. Although the building has experienced the occasional modification over the years, it is the sculptural and figurative decoration that has the widest range of later styles.
The supports backing onto the apses, almost all of the supports surrounding the Church perimeter and the first two columns starting from the presbytery, are Gothic in style: they have a circular central body backed to which are the little columns corresponding to the nerves of the ancient groined vaults on which the capitals are indicated by an impost of three cinctures and two cavettos.
This is a building of basilica-type design with three naves of equal height and almost identical width endeavouring to unify the space. The equal height of the naves makes Gothic flying buttresses unnecessary; hence recourse has been taken to robust buttresses between which are openings housing little chapels with Romanesque arches, many of which have been closed off due to the installation of altars.
With respect to the elements supporting the building, we can see how even respecting the first couple of Gothic supports, they subsequently introduced classical columns, consisting of simple, smooth single-cylinder shafts with attic bases and Doric-Tuscan capitals. At the foot of the epistolary nave three columns melt into one in order to support the weight of the tower. These impressive pillars are so characteristic of the style that the churches in which they are used are called "pillar" churches.
Curved or bent nerves join the keystones on the vault to create floral designs. One of these has straight nerves in an octagon shape. By using these star-shaped vaults, typical of Gothic architecture, and resting on pillars of Renaissance flavour, the "Basque-Gothic" style achieved "a combination of the two most beautiful ever architectural discoveries: the classic column, so aerial and harmonious, and the cross vault, which elevates and decorates spaces".
In the 17th Century, precisely in 1625, the main door was added to the Church on the north-facing wall to the rear of the building. A large vaulted arch stands in the Church wall, topped with eaves and framed by unassuming pilasters. This use of an arch to cover doorways, already employed in the 16th Century by Juan de Álava on San Esteban Church in Salamanca, was a popular resource widely used on many entrances to Renaissance temples in Spain.
The tower cap, the first part of which up to the height of the nave is doubtlessly original, was renovated in 1825 by Juan Bautista de Huici. This tower only had a very fleeting existence given that it was substituted in 1897 by the neo-Gothic cap now visible on the Church.
The stained glass windows, commissioned from ZETTLER in Munich, in addition to depicting the subjects imposed, had to be made on a polished, colourless base permitting the light to filter through them better.
The spaces for the big windows, in a unique Gothic style, had already been opened when the Great War broke out. The windows, which had by then left Munich via Amsterdam, didn't however arrive at the port of Pasaia. The openings had to be boarded up and left that way for four long years. At the end of the conflict, the parish priest was finally able to locate them in Amsterdam: the packaging was intact and not one single window had been broken.
The Parish Church of Errenteria is, as described by Lekuona, an art museum containing sculptures well worth the visit, such as the Souls altarpiece (part of a 15-16th Century Flamenco triptych).