The Łęczyca Royal Castle was erected by Casimir III the Great as a fortification during 1357–1370. Immediately after its completion, the Castle became a residence of king, and then was the seat of the governor of Łęczyca. In 1406 it was burned by the Teutonic Knights and rebuilt in the following years to serve as a place of a conference in 1409, where decisions were taken in connection with the approaching war with the Order. After the Battle of Grunwald many of the Teutonic Knights were incarcerated here. In subsequent years, four diets were held here (1420, 1448, 1454 and 1462), and the castle became the seat of the king Casimir IV Jagiellon during another war with the Order (1454-1466).
After a great fire in the second half of the 15th century the castle remained in ruins till the early 1560s. Then, in 1563–1565, Jan Lutomirski, Grand Treasurer of the Crown completely rebuilt the castle. The cost of the entire project amounted to nearly 3,000 florins, derived from the royal treasury. The disasters that struck the stronghold in the first half of the 17th century helped the Swedish General Robert Douglas, Count of Skenninge to take the castle, which was defended by starosta Jakub Olbrycht Szczawiński, during the Deluge in 1655. The destruction was completed in 1707 during another Swedish occupation.
Over the next years local residents used the remains of the castle as a source of building materials. After the World War II, the castle became the seat of the scout troop, and in 1964 reconstruction started.
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.