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:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.