Holsterburg was built by brothers Hermann and Bernhard Berkule before 1191. It was destroyed in local war in 1294. After its destruction, the Holsterburg was covered with a mound of earth, probably also for symbolic reasons, to erase the Berkule family and their ancestral seat from the memory of posterity. Under the hill, the complex has been preserved as it was in 1294.
The hill was excavated in 2010-2017 and castle ruins were cleaned.
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.