Hammershus is Northern Europe's largest medieval fortification, situated 74 metres above sea level. Erected in the 13th century, it was long believed that the castle was built as a private residence for the archbishop of Lund. However, new evidence found at the ruins of the castle suggests it was constructed in the beginning of the century as a royal residence for Valdemar II of Denmark and a base for the Danish crusades, according to Kjeld Borch Westh, superintendent of the National Museum of Denmark.
During a number of successive struggles between the kings of Denmark versus the Archbishopric, the fortress, serving as a refuge for the Archbishops, e.g. Jens Grand, was conquered by the king's army on a number of occasions, e.g. 1259, 1265, 1319, and 1325. In 1521, it was taken by king Christian II who used it to imprison Bishop Jens Andersen Beldenak of Funen. The fortress was conquered by forces of Lübeck the same year.
In 1658, Hammershus was occupied by Swedish forces but a rebellion on the island terminated the Swedish rule. The rebels led by Jens Pedersen Kofoed shot the Swedish commandant Johan Printzenskiöld and the Danish peasants traveled to Copenhagen to return the island to the king of Denmark. Corfitz Ulfeldt and his wife Leonora Christina were imprisoned in Hammershus 1660–1661, and the fortress was used as a prison on several other occasions.
The fortress was partially demolished around 1750 and is now a ruin. It was partially restored around 1900.
The fortification consists of the base castle residence and accompanying Mantel Tower, and includes a great stonewall stretching 750 metres around the castle grounds. Bricks found at the tower during the renovation led Westh and other experts to revise their theory on when the structure was originally constructed, moving back the date from around 1255 to the beginning of the century, when Valdemar became king.
Visitors to Hammershus have a spectacular view of the coastline and the sea surrounding Bornholm. South of the castle is a deep valley, water filled hollows, and dense forest. There are numerous points before arriving at castle where enemies could be stopped. The castle was built with box-like rooms surrounded by rings of fortifications. Each provided an additional layer of protection from invaders. Two natural spring ponds provided fresh drinking water on the side of the castle. Hammershus Fortress features a 750-metre-long perimeter wall and features a grand tower called the "mantel" tower.References:
Sirmione castle was built near the end of the 12th century as part of a defensive network surrounding Verona. The castle was maintained and extended first as part of the Veronese protection against their rivals in Milan and later under the control of the Venetian inland empire. The massive fortress is totally surrounded by water and has an inner porch which houses a Roman and Medieval lapidary. From the drawbridge, a staircase leads to the walkways above the walls, providing a marvellous view of the harbour that once sheltered the Scaliger fleet. The doors were fitted with a variety of locking systems, including a drawbridge for horses, carriages and pedestrians, a metal grate and, more recently, double hinged doors. Venice conquered Sirmione in 1405, immediately adopting provisions to render the fortress even more secure, fortifying its outer walls and widening the harbour.
Thanks to its strategical geographical location as a border outpost, Sirmione became a crucial defence and control garrison for the ruling nobles, retaining this function until the 16th century, when its role was taken up by Peschiera del Garda.