Lucheux Castle was built in 1120 by Hugh II, Count of Saint-Pol who used techniques taken back from the crusades he had been on. Situated on the border of Artois and Picardy it was one of the most important strongholds in the region. It continued to grow during the Middle Ages. Count Guy III of Saint-Pol altered the castle with four corner towers, hall and chapel in 1275. The castle was attacked by English army during Hundred Years' War several times.
In 1522 the imperial troops of Charles V besieged Lucheux castle for eight days and in 1552 Spanish army attacked it. Protestants took it into their possession in 1567 and the final siege occured in 1594-1595 by Spanish army again. They destoyed the castle and it was finally demolished by the order of cardinal Richelieu in 1640.
Today the massive gate and some walls remain.
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.