The castle of Arena was built by the Norman king Roger I the 11th century, to protect the pass of Berra and to defend the dominions on the Tyrrhenian side of the greenhouses against the risk of potential attacks from the eastern side, where Byzantines and Arabs had important positions.
The administrative and military control of the feud of Arena was entrusted to the Conclubet family, which for over 600 years was confirmed in power by the different dominations that succeeded one another in Calabria ultra, to which the Acquaviva dukes took over in the sixteenth century.
The ruins of the castle, substantially destroyed by the earthquake of 1783, preserve the Norman architectural structure, with large perimeter walls and the main building in the shape of a quadrilateral.
At the corners of the quadrilateral there are four partially preserved towers, belonging to different periods during which the castle underwent various technical – defensive adaptations.
Thus, in the Angevin age, the original quadrangular towers with smooth shoe of the Norman tradition, were replaced on the eastern side by high towers with a circular base and grooved shoe, the latter aimed at increasing the results of the so-called “plumbing defense” technique. increasing the range and lethality of the projectiles launched from the walls. Just the grooved shoe base is a constructive rarity since the typical Angevin tower had a smooth shoe.
On the western side, the Norman towers were modified only in the Aragonese period, when the development of artillery made it necessary to lower and strengthen them.
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.