The first castle in Xaintrailles is mentioned in 1259 as being held by three co-lords, all from the Xaintrailles family. It was built in the early 13th century, and what remains are the medieval outer courtyard, the keep, and the embankments of the south and west walls.
Jean Poton de Xaintrailles, a companion of Joan of Arc who died in 1461, followed by his successors Bernard de Lamothe and Antoine de Chamborel, governors of Casteljaloux, undertook constructions in the 15th century: two towers and the north residential wing. In the 16th century, turrets with fan-shaped projections were added to the south elevation, and moats and a drawbridge are mentioned in 1539. In 1570, the castle passed to the Montesquiou family, and later through marriage to the Lau de Lusignan family in 1724.
Around 1780, Armand de Lau, Marquis de Lusignan, had the moats filled in and an access arranged from the west. In 1824, the northeast rooms collapsed, and in 1843, the keep was partially restored based on the project of Gustave Bourières, the department's architect.
The oldest part of the castle is the 13th-century keep, with windows added in the 15th century. The north residential wing from the 15th century has one square floor and two attic floors with a hipped roof covered with flat tiles. Like the keep, it has an out-of-service staircase. The one-story and attic south building with turrets was renovated (kitchens). The west wing is flanked by two towers.
The U-shaped staircase and vestibule were added in the 18th century.
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.