Posert Castle, also known as Šabec (Schabez) and St. Martin, is a ruined fortress near the road between Paz and Šušnjevica, in municipality of Cerovlje. The ruins of the castle depending on the name are dating back to the 11th century (St. Martin), or 16th century (Šabec), while by archeological evidence to the second half of the 14th century. The castle was vastly devastated in the Uskok War (1615–17). Between 2009 and 2014 the castle was restored. Nearby the castle there is also a small Church of St. Martin from 1367.
The castle is of irregular trapezoidal layout with rectangular angle tower. The layout broad side is faced toward north. It consists of center in the northern part, and of external fortified yard in the central and southern part. The guard tower is best preserved. It had five floors, preserved to a height of 17 metres with irregular layout, 8 metres long by 6 metres wide.
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.