The first castle in Neath was located west of the river near the Roman fort of Nidum, and was a timber fortification in a motte and bailey structure. When Richard de Grenville founded Neath Abbey close by, he abandoned this original castle, and it may have been used by the monks as a source of building material.
A second castle on the opposite bank of the river, in what is now the centre of the town, is first documented in 1183; shortly afterwards, William de Cogan, son of Miles de Cogan, was appointed constable. This second castle was built by Gilbert de Clare, 5th Earl of Gloucester. During the 13th century, being a Norman stronghold, it was subject to attack by the Welsh, notably by Llywelyn the Great, who captured it in 1231 with help from a local Welsh lord, Morgan Gam. Following this, it was substantially rebuilt by Richard de Clare, 6th Earl of Gloucester, Gilbert's son.
It was taken again, and this time destroyed, by Humphrey de Bohun, 4th Earl of Hereford, in 1321, during the rebellion against King Edward II of England. Its owner, Hugh Despenser the Younger (who had gained the lordship through his marriage to the heiress Eleanor de Clare), rebuilt it, possibly with the addition of a gatehouse. In 1376, one Roger Kyngot was the constable, and the castle was rebuilt in stone in 1377; that is probably when the great gatehouse was built, which is the main surviving feature. The castle was in use until the 17th century, and has been a recreational area for the town since the 18th century.
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.