The ruins of Castillo de Altafría stand atop a hill overlooking the village of Valderas in León, watching over the Cea River valley for centuries. A captivating local legend, passed down through generations, asserts that this medieval fortress once possessed deep, secret tunnels excavated into the earth. According to oral tradition, these underground galleries provided a direct connection between Altafría and two other key defensive bastions in the region: the Castle of Benavente and the fortress of Grajal de Campos.
Construction of the castle dates back to the 12th century during a period of intense rivalry among Hispanic kingdoms. It was promoted by King Fernando II of León, who reigned from 1157 to 1188, with the specific purpose of establishing a solid defensive outpost to monitor the Cea River line. At that time, the river served as a highly strategic border between León and Castile. Situated at an altitude of 850 meters, the castle allowed for control over the river crossing and the adjacent path against the ambitions of the Castilian king Alfonso VIII.
The strategic role of Castillo de Altafría reached its peak historical relevance in the early 13th century during regional dynastic disputes. In 1206, the fortress featured prominently in the diplomatic clauses of the Peace of Cabreros treaty, through which King Alfonso VIII of Castile handed control of the castle to his grandson, the future monarch Alfonso IX of León. Later, in 1218, the kings signed pacts regarding the handover of Valderas, agreements that anticipated the definitive union of León and Castile.
Over subsequent centuries, the castle underwent significant transformations in its lordship and architectural functions. In the 14th century, the fortification and the lordship of the Seven Villages of Campos became part of the heritage of the noble Osorio family. Don Juan Álvarez de Osorio established his habitual residence there, strengthening the lineage's link to Valderas. The Osorio family maintained possession until the 16th and 17th centuries, after which they abandoned it, leading to a gradual decline.
From a historiographical perspective, specialists have analyzed the origin and veracity of the famous legend regarding underground tunnels. Historians agree that the existence of kilometer-long galleries connecting Altafría, Benavente, and Grajal de Campos lacks documentary basis. Given the geographical distance between these fortresses, the construction of such passages is considered unfeasible for the Middle Ages. However, experts explain this popular myth by pointing to Valderas' subterranean heritage, characterized by deep traditional wine cellars with stone vaults. Popular fantasy transformed these historic winemaking galleries into a narrative of secret military passages.
Today, the appearance of Castillo de Altafría bears witness to the impact of passing centuries. Of the original military structure, two sober towers built of rammed earth and a section of wall remain standing. Despite its evident deterioration, the monument enjoys legal protection as a Cultural Interest Asset. Nevertheless, it appears on Hispania Nostra's Red List of threatened heritage due to the risk of collapse caused by moisture leaks and deep cracks in its walls, making restoration urgent.
The castle ruins are integrated into the valuable historical complex of Valderas, a village declared a Cultural Interest Asset in 2008. Originally, the fortress was connected to the first urban wall descending the hill toward the Arco de las Arrejas. This Mudéjar gate still retains the groove of the portcullis, serving as an exceptional testimony of defensive architecture. In the 14th century, King Juan I granted the village a Great Privilege, exempting it from taxes and fostering great prosperity. Fruits of this flourishing era include the Palacio de los Osorio, the Palacio de Castrojanillos, and the emblematic porticoed squares.
Sources: elDiario.es.