Jettenbach Castle was first mentioned in the mid-12th century when it was probably a wooden fort. The castle chapel originates from 1356. The castle was replaced by a stone castle in 1511 and expanded in 1622. The other wing was added in the late 17th century. The new brewery was constructed in 1726.
Jettenbach was badly damaged by fire in 1855. It was rebuilt in next two years to the current appearance.
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.