Now known as La Colegiata de Santa Juliana its origin comes from the expansion of the old monastery of the same name in the mid-twelfth century. It was built by a group of monks to contribute to the repopulation of the area and create a small chapel in which to expose the relics of the martyred Juliana, which they brought with them. At that time the village took its name from the monastery: "Sancta Luliana, which declined in the current Santillana.
Today there are the remains of the original monastery. It is assumed that it was a simple stone building with a rectangular apse and covered with wood, like other buildings Visigothic or Mozarabic. In the current structure of the church, the style is influenced by the Romanesque style by currents from the south, from the Camino de Santiago through the provinces of Burgos and Palencia. Its main facade is oriented to the south and preceded by a large atrium, it has a semicircular arch archivolts surrounded by a frieze depicting the Pantocrator and a niche with the image of Santa Juliana in the frieze. Their spires reflect a variety of floral and figurative Romanesque iconography.
The cloister is located on the north side of the ensemble and their heads are the main decorative elements used in the period, floral, geometric and figurative. Predominate double arches on columns, but there are also four column pillars, functioning as topic separators. Among the subjects (topics) depicted are scenes from the Old and New Testaments.
It is a noteworthy altarpiece, made between the late XV and early XVI century which blended elements from the Flamboyant Gothic and plateresque period.