Auenstein Castle was built on a rocky hill above the Aare river in the 13th century for a local nobleman named Gowenstein. Around 1300 it was acquired by the Lord of Rinach. During a war between the Habsburgs and the Old Swiss Confederacy in 1389, a Bernese army sacked and burned the castle. Following the Bernese conquest of the Aargau in 1415, Auenstein became a part of the Landvogtei of Lenzburg. Over the following decades, the Lords of Rinach were not able to rebuild the castle and in 1465 Albrecht von Rinach sold the ruins and surrounding villages to Heinrich Hasfurter from Lucerne.
The castle remained ruined, but over the following centuries the ruined castle and the attached Herrschaft passed through several owners. In 1732 the castle and territory came under direct Bernese control and for the following half century it remained that way. Until the 1798 French invasion and the Helvetic Republic swept away the old medieval system of noble landlords who ruled over villages and estates. With the creation of the Canton of Aargau in the 1803 Act of Mediation the ruins became the property of the new canton.
In the 1850s the ruins were sold to a private owner who began building a new castle from the ruins. By 1858 there was once again a habitable castle on the site. The new castle was sold several times until in the early 20th century Mrs. A. Hoffmann acquired Auenstein. She renovated and expanded the castle and in 1927-29 it reached its current appearance. Today it is private use.
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.