Gamleborg, also known as Gamleborg Viking Fortress, was the first fortress on the Danish island of Bornholm. Built around 750 AD, it was the seat of the kings of Bornholm during the Viking age (750–1050) and early Middle Ages (1050–1150). The massive fortress is 264 metres long from north to south and 110 metres wide from east to west, with gates to the north and southwest. Around 1100, significant alterations were made and it was reinforced, but it was abandoned soon afterwards in favour of Lilleborg Castle, roughly 700 metres to the northeast.
The fortress is Bornholm's oldest defence works. Its builder is unknown, but an account of the Baltic Sea travels of Wulfstan of Hedebyin 890 tells us that Bornholm already had its own king at the time. There is, however, firm evidence that the fortress was in use during the reigns of Harald Bluetooth (940–986) and Canute IV (1080–1086). The Gamleborg fort was used as refuge during the tenth century against Viking raids. Gamleborg was abandoned in 1150, the occupants moving to Lilleborg, only 700 metres to the northwest. It is not known why the move was made but it does not appear to have been the result of hostilities. Excavations in the 1950s showed the fortifications originated in the Viking period although there is evidence the site was used as a hideout in the Iron Age. The ruins that can be seen today are mainly the result of reconstruction work completed in about 1100.References:
Krickenbeck moated castle is one of the oldest on the lower Rhine. Its history dates back to the year 1104, when the castle was first mentioned. It is unclear why the old castle, which was certainly inhabited by Count Reginar, was abandoned or destroyed. In the mid-13th century the castle was moved to the current location. At the end of the 14th century the new castle belonged to the Counts of Kleve.
Johann Friedrich II of Schesaberg converted the castle into a Baroque mansion between 1708-1721. On September 7, 1902, a fire destroyed the entire mansion. From 1903 to 1904, a three-winged castle was built in the Neo-Renaissance style. Today Krickenbeck is a conference center.