Located in the old quarter of Avilés, this church is one of the town's main signs of cultural identity. Its single nave and a semi-circular apse correspond to its construction in the 13th century. However, the church was considerably modified in the 17th and 18th centuries, with the opening of large bays and the elevation of its walls and roof.
The materials used are masonry in the walls and ashlar for the main façade. The original Romanesque bays in the walls and apse were bricked off during the Baroque period, being replaced by other broader windows in the 17th century.
As regards the outside decoration, the church retains two fine portals in the southern and western walls. The south wall forms a body jutting out of the building covered by a tiled roof secured by corbels. It comprises a semi-circular arch with three archivolts resting on columns and capitals decorated with masks and plant motifs.
The western portal, the main entrance to the church, is more stylistically advanced. This body also juts out of the building with tiled roofing secured by corbels and pointed arches with four archivolts resting on columns and capitals decorated with zoomorphic and anthropomorphic motifs.