The Castle of the Bishops of Sigüenza stands on the highest point of the ridge above the town, commanding views over the surrounding plateau and the Henares valley. It was built by the bishops of Sigüenza in the 12th century as both a residence and a defence, and remained in ecclesiastical hands for most of its history. The walls and towers follow the contour of the rocky outcrop, giving the building an organic relationship with its setting that is more impressive than any formal architectural plan.
Today the castle operates as a Parador Nacional, the Spanish state hotel chain specialising in historic buildings. You do not need to be a guest to walk up to the exterior and appreciate the building's position over the town; the courtyard and some areas are accessible to non-guests. The combination of the cathedral below and the castle above gives Sigüenza an unusually complete medieval townscape, with the two poles of medieval power — church and fortress — still clearly readable in the landscape.