Built on the site of an Celtic oppidum, the castle of Pons was an important medieval stronghold due to its location as a hub of roads including those for the pilgrims of Saint James. It belonged to the lord of Aulnay, Charente-Maritime, to the dukes of Aquitaine, then to the lords of Pons. Razed in 1179 by the Duke of Aquitaine Richard Lionheart following a revolt of his vassal, the castle was rebuilt in 1187 by Geoffroy III de Pons with the addition of the imposing quadrangular Keep of Pons, partially over of the foundations of the original, smaller keep and partially over new foundations. Based on the chapel facade, it is believed that the chapel was also rebuilt during this period.
The castle was again destroyed in 1622 (with the exception of the keep and some defensive elements) by the armies of Louis XIII following the siege of 1621. A few years later, Marshal Caesar Phoebus d'Albret had the current main building erected. Despite its cold appearance, several rooms within the Keep have comfortable interior with wooden ceilings and mounted canvas decorated with allegorical figures. The base of the ramparts has been partially preserved, and forms a walk from which one can enjoy a panoramic view of the Seugne valley. Caesar Phoebus d'Albret, Sire de Pons, ordered the construction of the monumental staircase which connects the upper city to the lower city.
The buildings and vestiges of the medieval castle were bought in 1806 by the municipality. Only the Castral Chapel and the Saint-Gilles porch, the Keep and the ramparts on the cliffs are the remains of the medieval fortress. The municipality set up the esplanade in the public garden and repurposed the main building as the town hall.
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.