The Castle of the Masovian Dukes in Czersk was built on the turning point of the fourteenth and fifteenth century by Prince Janusz I. When the Masovian land became part of the Kingdom of Poland - which was under the rule of Queen Bona Sforza. Primarily, the castle had three towers, one of them - being four-sided, was used as the main gate house.
During the war with the Swedes, in 1656, the castle became partly ruined. The retreating land army, close to Warta, under Stefan Czarniecki"s commandhad captured the stronghold and had devastated it. The castle went through a reconstruction between 1762-1766, when Marsza³ek Franciszek Bieliñski had commanded the reconstruction of the stronghold. However, due to the Prussian Partition, the Prussian leader had ordered for the demolition of the castle"s defense walls, reducing the stronghold"s military importance. From that time, nobody had every again took on the reconstruction of the castle. From the once mighty stronghold, all of the towers; a brick bridge from the eighteenth century; and the north and east wing of the castle had all survived.
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.