Okoř is a castle on a low rocky promontory in Okoř, north-west of Prague, about 15 kilometres from the city centre. In 1228 a stronghold was built in the small hamlet of Okoř. It was later modified into a Gothic castle, founded in 1359 by Frantisek Rokyčansky, a wealthy burgher of Prague's Old Town. It was later modified by comprehensive Late Gothic remodelling by the Lords of Donin. In 1518, during the reign of Bořitas of Martinice, the castle was turned into a residence in the Renaissance style.
During the Thirty Years' War the castle was heavily damaged and then restored in the Baroque style. It underwent further extension in the second half of the 15th century, and in the 17th century it was owned by Jesuits. Following their departure after the Jesuit order was discontinued in Bohemia, the Okoř castle became deserted in the late 18th century and slowly began to deteriorate.
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.