Castle Aguilar de Campoo is a Romanesque fortress dating to the 10th or 11th century, rising prominently from the Aguilón rock that overlooks the town of Aguilar de Campoo in Palencia. Built atop earlier Celt-Iberian structures, the castle displays trapezoidal design with circular towers at its corners and an arched entrance. The visible structure largely represents reconstruction from the 12th century, with additional walls and fortifications added by the Manrique family in the 15th century. Declared a Historic-Artistic Monument in 1949, the castle stands as a significant example of medieval military architecture in Castilla y León, despite its current ruined state.
