Built in the 12th century in mudejar style, the Castilnovo castle is conserved in good condition. It has a rectangular plan, with six round and square towers. It was rebuilt in the 14th - 16th centuries and again between the 19th and the 20th centuries. The present castle is thought to have been built on a previous structure, probably a small fortress. Trapezoid ground plan, with six round and rectangular turrets of brick and masonry. Arched, parted windows. Rectangular turrets, one if which leads inside the building.
Particularly noteworthy is a corner turret reminiscent of another turret in Monteagudo de las Vicarías. The main features of the building are 14th century.The southern section, with its wooden gallery, dates back to 1861, and the present stone yard was built in the 20th century.
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.