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 Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.