Cuéllar Castle is conserved in good condition, and it has been built in different architectural styles between the 13th and 18th century. Much of the castle in the Gothic and Renaissance styles. The military building was extended and transformed in the 16th century, turning it into the palace of the Duke of Alburquerque. Among its historical owners, stands out Álvaro de Luna and Beltrán de la Cueva, as well as the successive Dukes of Alburquerque.
The Dukes of Alburquerque lived in this castle for centuries until they moved to Madrid to be close to the court. Thereafter their use of the castle was as leisure and holidays palace, abandoning the building slowly. At the late 19th century the castle was almost completely abandoned, and was victim of robberies. In 1938 was a political prison was settled within the castle, and after was established also a sanatorium for prisoners affected by tuberculosis. It was used as prison till 1966.
In 1972, the Department of Fine Arts carried out an intensive restoration, and made it the home of a Vocational Education school, which continues to this day.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.