Aspelt Castle is a Baroque residence built in 1590 on the site of a medieval castle. The origins of Aspelt Castle date back to the 11th century when a fortified castle with a moat was built on the site, possibly on Roman ruins. The first written reference to the castle can be found in Theoderich von Wied's Echternach chronicles from 1132. The foundations of the round Gothic towers are probably from the 14th century while the current building was completed in 1590 following transformations carried out by the Ruelle, Kempt and Burthé families. In 1777, the Martinys extended the palace and installed new Baroque windows in the towers. In 1957, the ground floor of the south-west tower was restored.
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.