The Castle of Osma is a medieval castle which seems to have been built in the 10th century. It was built in stone, although Count Gonzalo Tello used some Roman structures and materials which belonged to a small Christian fortress.
The castle is divided into three walled enclosures which can be easily distinguished. Nowadays you can see the ruins of this fortress which adapts perfectly to the rocky hill between the Ucero and Abión rivers, near the famous Roman city of Uxama. It was used mainly as a defensive structure located in the natural passageway to this valley and the City of Osma. Some of the walls of the main enclosure are still standing which help to make out the floor plan and you can still see its Keep, remains of other towers, the access gate and a small door. There are also remains of the other two enclosures that improved the castle’s protection. On the outer wall that goes down the hillside, you can see the Water Tower (Torre del Agua) that is located near the river.
The Castle of Osma has experienced many battles from its first reconquest in 912 all the way up to the last in 1088, and in the 15th century, it belonged to the bishop of Osma.
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.