A forgotten prison for Castile's usurper king

The Castillo de Portillo, a medieval castle in Portillo, [Castile and León](https://en.wikipedia.org/wiki/Castile_and_León), [Spain](https://en.wikipedia.org/wiki/Spain), has been fortified since the 10th century. It was built as a defense against Moorish forays led by [Abd al-Rahman III](https://en.wikipedia.org/wiki/Abd_al-Rahman_III). In the 14th century, it belonged to the family of [Sandoval](https://en.wikipedia.org/wiki/Sandoval). In 1392, it was confiscated from Diego Gómez de Sandoval in the name of [King Juan II of Castile](https://en.wikipedia.org/wiki/Juan_II_of_Castile), who later granted it to [Ruy Díaz de Mendoza](https://en.wikipedia.org/wiki/Ruy_Díaz_de_Mendoza).

From 1448 to 1452, Portillo was occasionally held by Juan's favorite, [Don Álvaro de Luna](https://en.wikipedia.org/wiki/Álvaro_de_Luna), although the fortress remained in royal hands. Don Álvaro, however, fell from favor and was imprisoned at Portillo. In 1464, [King Enrique IV of Castile](https://en.wikipedia.org/wiki/Enrique_IV_of_Castile) conferred the site upon Alfonso. [Juan Pacheco](https://en.wikipedia.org/wiki/Juan_Pacheco), the prince's tutor, held the site until his death in 1474.

The castle passed to the family of [Osuna](https://en.wikipedia.org/wiki/Osuna,_Spain) in the 19th century. Today, the castle stands as a national monument and property of the [University of Valladolid](https://en.wikipedia.org/wiki/University_of_Valladolid).

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons