Fort Vechten was constructed between 1867 and 1870 as part of the so-called Nieuwe Hollandse Waterlinie (The 'New Dutch Water Line') to defend the cities of the western Netherlands from overland attack.
The history of Vechten dates however back to the Roman times. The Romans, who apparently chose the spot because it controlled a side-arm of the Lower Rhine, built their castellum by the year 4 AD, and possibly named it after that river, Fectio. This fort was quite important from time to time as a supply-base for the invasion of Germany. It attracted the local population as well, which came to settle in the vicus at either end of the fort. The castellum was most likely abandoned by the late 3rd century, when the Roman Empire faced crisis after crisis. However, the main reason that the army never returned may well have been because the access to the fort silted up, which caused it to become land-locked, with all the ensuing logistical problems. The neighboring castellum at Trajectum/Utrecht may have supplanted it as local fort. Today there is a reconstructed Roman watch tower.
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.