The Ahrensburg village came into the possession of the Cistercian Reinfeld Abbey in 1327. After the dissolution of the monasteries due to the Reformation, the whole area came into the possession of the king of Denmark. He rewarded his general Daniel Rantzau 1567 with lordship over these villages. His brother and heir Peter Rantzau built a Renaissance residence in the form of a water castle, now the symbol of the town, and the castle church around 1595. The new schloss buildings were made with parts of the torn-down mansion, on a rectangular island surrounded by a defensive moat. The following year, the chapel was completed. It was modelled on Schloss Glücksburg, built a few years earlier. Four octagonal towers were added later with copper-covered torn heads and lanterns.
The Rantzaus' estate was heavily indebted by the middle of the 18th century and, in 1759, was acquired by the businessman Heinrich Carl von Schimmelmann. Schimmelmann remodelled the castle and village in the baroque style and the current layout of the town reflects these plans.
Historians in Germany consider the building one of Schleswig-Holstein's best-known Renaissance buildings and attractions. Open to the public, it is surrounded by an English park, a chapel, a watermill and a museum.
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.