The first true knowledge about the foundation of the St. Vitus abbey dates back to a document from the late 11th century, probably from the scriptorium of the monastery of Gladbach. This richly illuminated document reports that a nobleman long before the founding of the abbey would have erected a church on the top of the hill, a church destroyed by the Magyars in 954.
In 1120, at the latest, the monastery was affected by the Benedictine reform Siegburg. The nave of the abbey got its definitive form between 1228 and 1239. Between 1256 and 1277, while reconstruction was developing, the idea of building a new choir appeared, but on a different plane (the typical elongated choir of the Gothic style). In order to carry out this plan, Master Gerhard, the first architect of Cologne Cathedral brought to his experience. Albert the Great consecrated the abbey on April 28, 1275.
The old Benedictine monastery church was elevated in 1973 to the rank of Minor Basilica by Pope Paul VI.
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.