The development of the village of Santillana started in the early Middle Ages. Between the 8th and 9th centuries, a small religious community supported by the Astur kingdom settled in a place known as Planes, founding a monastery in which the relics of Santa Juliana de Bitinia are kept. This martyr (Santa Illana), to whom the building is dedicated, finally gave her name to the village in the 12th century.

Since the 9th century, the economic power of this monastery and the religious significance of Santillana, became consolidated (the coastal branch of the Camino de Santiago reached this village). The spiritual and material splendour, which increased with the granting of the first "fuero" to the monastery in 1045, led to the transformation of the abbey into a collegiate church and the renovation of the Roman-style factory late in the 12th century.

In the 13th century, the monasterial domain of Santillana decayed becoming a collegiate church which depended on the Diocese of Burgos. However, the village became the capital of the Merindad of Asturias de Santillana and the permanent headquarters of the merino. The power of the noble families was gradually increasing leading, in the 15th century, to the conversion of Santillana into a marquisate under the House of Mendoza.

Its monasterial domain and later, its resident nobility made of Santillana a conventual and majestic village, as reflected in its rich artistic heritage.