The origins of Puente del Congosto Castle dates from the 12th and 13th centuries. It was built for defensive reasons, to control the route which connected Ciudad Rodrigo with Avila.
In 1393, Enrique III granted the manor of the Puente del Congosto to Gil Gonzalez Davila, which rebuilt the castle, which would be Posada Real. The Duke of Alba bought the castle to the Emperor Carlos in 1539, adding to the rectangular tower the large cube gives to the building most uniqueness.
The castle is in a good state of conservation. It is made up of an outer enclosure and an inner fortification formed by a great rectangular keep with a second tower build against it.
The outer enclosure is an irregular rubblework hexagon, reinforced in the corners by granite ashlars. Because it is more vulnerable than the others, the western curtain wall of the outer enclosure is extra protected with a small tower in its center. The gate is situated in the northern wall and is protected by another wall. There is also a postern in the eastern wall on a higher floor level.The keep is made up of two great halls with brick vaults sustained by arcs of ashlar masonry. In the lower hall, on a height of about 3 meters in the western wall, is the entrance to the spiral staircase that leads to the upper hall. In the eastern wall is a little window. The top of the keep was originally crenelated.The ground floor level of the second tower is only the one that can be accessed from the courtyard. All the higher floor level in this tower can only be accessed through wall staircase from the keep.
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.