First mentioned in historic documents in 1254, Burg Groppenstein was built in a particularly beautiful place, where the River Mallnitz flows into the River Möll. In the 15th century it was turned into a defence in the style of the late Middle Ages. In 1872 the castle was renovated by the Viennese architect Adolf Stipperger, and its exterior design has since been unchanged.
The Romanesque wing was replaced by Gothic dwellings and weirs with towers and battlement walls. The Knights Hall features beautiful, 16th century stained glass windows. Other glass paintings were added by Prof. Franz Chvostek, who owned the castle from 1936 to 1944.
Also worth a visit is the castle chapel consecrated to St. Katharina with its gothic aisle and semi-circular Romanesque apse.
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.