Weissenau Castle was first mentioned in the historic record as castrum Wissenowe in 1298. It is unclear whether it was built by the Lords of Rotenfluh (Unspunnen) and then given in fief to the Freiherr of Weissenau or if it was built by the Weissenau family as the center of their estates. The castle was built on what was an island at the mouth of the Aare river into Lake Thun. In the intervening centuries, the waterway silted up and the island became connected to shore. The market town of Widen grew up across the channel from the castle and in 1362 was connected to the castle by a bridge. Around 1334, the Freiherr of Weissenau joined other local nobles in a war against the growing power of the city of Bern. After the defeat of the nobles, Weissenau was forced to sell the castle and Widen to Interlaken Abbey to pay his debts. In 1365, the Abbey moved the weekly markets and yearly fair away from Widen and to the village of Aarmühle (which is now Interlaken). Losing the market devastated Widen and it began to decline.
In 1528, the city of Bern adopted the new faith of the Protestant Reformation and began imposing it on the Bernese Oberland. The Abbey and its villages joined in an unsuccessful rebellion against the new faith. After Bern imposed its will on the Oberland, they secularized the Abbey and annexed all the Abbey lands. Weissenau Castle and the small village of Widen became a part of the Bernese bailiwick of Interlaken. The castle was used as a prison into the 16th century, but began to fall into disrepair and eventually collapsed. In 1655 and again in 1700 the bailiwick made plans to renovate and repair the castle. However, neither plan was implemented.
Today only ruins remain of the castle. The castle residence and tower, portions of the castle building and the curtain wall are all still standing.
References:Rosenborg Palace was built in the period 1606-34 as Christian IV’s summerhouse just outside the ramparts of Copenhagen. Christian IV was very fond of the palace and often stayed at the castle when he resided in Copenhagen, and it was here that he died in 1648. After his death, the palace passed to his son King Frederik III, who together with his queen, Sophie Amalie, carried out several types of modernisation.
The last king who used the place as a residence was Frederik IV, and around 1720, Rosenborg was abandoned in favor of Frederiksborg Palace.Through the 1700s, considerable art treasures were collected at Rosenborg Castle, among other things items from the estates of deceased royalty and from Christiansborg after the fire there in 1794.
Soon the idea of a museum arose, and that was realised in 1833, which is The Royal Danish Collection’s official year of establishment.