In the center of Santillana del Mar, we can visit a Romanesque National Monument called La Colegiata de Santa Juliana, or better known as the Collegiate Church of Santillana.
The collegiate church of Santa Juliana, declared a historical monument in 1889, was built in Romanesque style in the middle of the 12th century. This is the time when an old monastery, founded in the seventh and ninth centuries to house the relics of Saint Juliana of Bithynia (Santa Illana, from which the name of the town comes…), becomes a collegiate church, by changing the monastic rule that governed it to the one of the canons of San Agustín.
The most important building in the architectural complex is the church, which uses San Martín de Frómista as a model, in Palencia, although it surpasses it in size. It consists of a head with three apses of semicircular plant, which are covered with furnace vault and cannon in the straight section of the central apse, larger than the lateral ones. The transept has cannon vaults in its lateral sections, while the central one has a dome on pendentives and false nerves, which are the product of a reconstruction of the eighteenth century, after the collapse of the dome on original horns. The body of the church is formed by three naves separated by cruciform pilasters, the central being higher and wider than the lateral ones.
The main facade is located on the south facade, which has an upper frieze with various reliefs in the form of apostles and saints, surrounding the Pantocrator. In the 18th century a triangular pediment with the image of Santa Juliana was added, in addition to the gallery of hoops that stands on the nave of the epistle.