The Church of Santo Adriano was founded by King Alfonso III and his wife, Jimena, in 891. It is rectangular in shape with three naves separated by semi-circular arches on square stone pillars. It has a gable roof and rectangular triple apse with barrel vaults, the highest being in the central chapel. Above this apse there is a room only accessible from the outside through a mullioned window.
The porch at the west end, which comprises three bodies, was used in modern times to lengthen the church.
Of the side structures that formed the original layout, only the south structure is conserved, serving as the sacristy.
The most important decorative remains are the mural paintings, mainly in the main chapel, dating from the time the church was built.
It also preserves a tombstone dating from 1108, remains of a marble rood screen, a small semi-circular arch and a pair of columns with capitals with leaf motifs on the triumphal arch. The bell gable was built in the 17th-18th centuries.
The church underwent several restorations and remodellings: the first in 1108, in 1950 (carried out by Luis Menéndez-Pidal y Álvarez), in 1983 and 1987-1988 (by the Regional Ministry of Education, Culture and Sports).
