Clemency Castle is small residential manor adjacent to the church was built in the 1660s in the Renaissance style. It had fallen into disrepair but was fully renovated in 2009 and is occasionally open to the public.
The castle was built in 1665 by Johann Ferdinand von Blanchard, a sire of Clemency. For building materials, he used the ruins of an earlier castle which stood on a site some 30 metres away from today's castle. Fifty years later, it was transformed into the Baroque style of the times. In 1721, after von Lanser had bought the property, it once again underwent transformations. In 1982, Jean Weis acquired the property which was inhabited until 2004.
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.