Loevestein Castle (Slot Loevestein in Dutch) is a medieval castle built by the knight Dirc Loef van Horne (hence 'Loef's stein') between 1357 and 1397. It was built in a strategic location where the Maas and Waal rivers come together. At first it was a simple square brick building, used to charge toll from trading vessels using the rivers. In the 16th century (around 1575, orders given by William the Silent) it was expanded to a larger fortress surrounded by earthen fortifications with two (later three) stone bastions on the northern side, two moats, an arsenal, and housing for a commander and soldiers.
Loevestein changed hands twice between the Northern Dutch and the Spanish (December 9, 1570 it was taken by the Geuzen, ten days later Spanish again, and from June 25, 1572 Dutch till this day), the warring parties of the day. The castle became a prison for political prisoners in 1619. One famous inmate was the eminent lawyer, poet and politician Hugo de Groot (Hugo Grotius) often presented as the 'father of modern international law', who was serving a controversially imposed life sentence from 1619. In 1621 Hugo de Groot managed to pull off a daring escape in a book chest. The idea for this escape came from his wife Maria van Reigersberg (also living in the castle). He subsequently became the Swedish Ambassador to France for 10 years. Another high profile inmate was the English Vice-Admiral George Ayscue.
Until the Second World War Loevestein Castle was part of the Nieuwe Hollandse Waterlinie, the main Dutch defense line that was based on flooding an area of land south and east of the western provinces. Currently the castle is used as a medieval museum and function centre.
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.