The Castle of Cuellar dates mostly from the 13th century. Its most interesting feature is the distribution of the church apses interwoven with the walls. Don Beltrán de la Cueva was responsible for the palace section.
It preserves arched doors and upper defensive chambers, one of which was left inside the castle. King Enrique IV took it away from his step-sister, Isabel, who had inherited it from her father Juan II, and gave it to his main assistant, don Beltrán de la Cueva, who built a new and sumptuous castle-palace which his successors finished in the 16th century.
It once housed an excellent collection of weapons.
During he War of Independence, it was used
by the French General Hugo, the father of Victor Hugo, and was
Wellington's military headquarters. Its was subsequently made
into a prison, where Espronceda spent some time.