It is not known with any certainty when Dill castle was built, but it is assumed that this happened in the 11th century, and that it might have been built on the ruins of an earlier Roman or Celtic complex.
At the complex's highest point, in the north, is the Oberburg (“upper castle”). Not much of the four-floor residential tower, whose sides measured 18 × 12 m, is left other than three outside walls; the east wall is missing. On the north wall's outer side is a garderobe. Parts of the barrel-vaulted cellar may still be visited. West of the upper castle, remnants of the girding wall have been unearthed. They exhibit a herringbone pattern in their construction.
On the area of the Niederburg (“lower castle” or “bailey”) to the east stand an Evangelical church, built on the spot where the castle chapel once stood, a wellhouse, which has been expanded into a holiday home, and a modern house.
Of the Vorburg (“forward castle” or perhaps “outer bailey”) to the west and south, only remnants of the foundations and outer wall can still be found. Part of the area is used as a garden.
The castle is in private ownership and normally cannot be visited. However, once or twice a year, there are guided tours. The times are published.
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.