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 Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.