Clairmarais owes its origin to the famous Cistercian abbey founded by St. Bernard in 1140. He gave the village the name of Claromarisco (later to be Clarus Mariscus and then Clermarez) because of the huge marshes and many rivers in the vicinity. The Dutch Klaarmares and West Flemish Cleremeersch names reflect the nature of the terrain, too. Clairmarais became a fully-fledged common in 1790 when the abbey was going to be destroyed and sold as a national asset during the French Revolution.
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.