The Castle of St. George (Castello di San Giorgio) was built from 1395 and finished in 1406 under commission by Francesco I Gonzaga, designed by Bartolino da Novara, one of the most renowned military architects of the time. It has as square plan with four corner towers, surrounded by a ditch with three entrances, each one with a drawbridge. In 1459 architect Luca Fancelli, commissioned by marquis Ludovico III Gonzaga, who assigned several rooms of the Corte Vecchia for the Council of Mantua called by Pope Pius II, restored the castle, which lost definitely lost its military and defensive function.
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.