The church of Sant Esteve is a good example of Catalan Romanesque construction of the eleventh century and features an important crypt. Alongside it, the modernista cemetery of Bernardí Martorell is a unique example of the integration of architecture and nature in Catalonia.
The documentation mentions several religious establishments in the municipality of Olius dating from the tenth century. However, the consecration of the church of Sant Esteve dates back to 1079. It appears that the parish was built by the people of the area as a group. This harmonious construction has all the features of the Catalan First Romanesque. The church has a single nave with a barrel vault reinforced by transverse arches. The exterior representation of the latter is observed through the buttresses, which add rhythm to the side walls of the building. Inside, these side walls are reinforced by a series of side arches that afford richness to the architecture while distributing the forces in the wall. The church is crowned by a semi-circular apse with a quarter-sphere roof and the exterior displays decorative features in the form of blind arches and pilasters. Both the sanctuary and the presbytery space are constructed above ground level, since below the latter lies a semi-underground crypt. This crypt, which follows the profile of the upper level, has 6 columns, some of which may have been re-used from an earlier church. These create three naves with a groin vault roof. The crypt is currently entered via a central stairway built in the 17th century, but it was originally accessed by two side stairways of which some evidence still remains. The advocation of the lower space is to Saint Mary.
Video on the site of Sant Esteve d’Olius