Castillo de Arcos de la Frontera, also known as the Castillo Ducal, is a medieval fortification in Arcos de la Frontera, Cádiz province, situated in the Plaza del Cabildo at the highest point of the town. Originally built by Muslims in the 11th century as a military alcázar, it was modified by Christians during the 14th and 15th centuries following its conquest by Alfonso X's forces in 1264. Later transformed into a residential palace by the Ponce de León family, the castle features an irregular quadrangular plan with three major towers with battlements and is organized around a large central courtyard. Protected as a Cultural Heritage Site since 1993, the privately owned fortress remains an important example of medieval military-to-residential transformation.
