Ducové is famous for an archaeological site on the Kostolec hill, where an important Great Moravian castle has been unearthed. The castle, including a small palace, a Christian rotunda church, and a graveyard of local nobles, served as the administrative center of the Váh river valley during the 9th century and the first half of the 10th century. It was founded after the nearby Nitrian castle in Pobedim was destroyed during unification of Great Moravia by Mojmír I.
Ducové castle was destroyed itself by Magyar invaders around 955. Some parts of the castle (such as its palisades) have been reconstructed by archaeologists. Excavations of older settlements from the Stone Age, Bronze Age and the Roman era indicate that Ducové benefited from its location on the Amber Road well before the Great Moravian era.
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.