The Castillo de Palenzuela commands a strategic position at the eastern edge of the town, dominating the Arlanza valley from its right bank near the confluence with the Arlanzón river. Documented in historical records dating to 850, Palenzuela served as the capital of an administrative district and later the Merindad del Cerrato. The settlement's medieval importance is underscored by Arab raids in 919 and King Juan II's significant royal courts held there in September 1425 during the town's period of maximum splendor. The fortress reflects centuries of military importance in regional affairs. Today, standing remains include portions of the northeast wall and three talus-based towers that have lost their dressed stone facing, revealing interior rammed earth construction with visible gaps for wooden lattice reinforcement. Fragments of additional walls and the foundation of a third tower complete the visible ruins, offering archaeologists and visitors insight into medieval construction techniques employed in northern Castile.
