Weissenau Castle, Interlaken

Weissenau Castle is a fascinating ruin located in the municipality of Unterseen, within the Canton of Bern, Switzerland. As a Swiss heritage site of national significance, it holds a storied past that dates back to its first mention in historical records in 1298 under the name Castrum Wissenowe. The origin of the castle remains somewhat unclear—it may have been constructed by the Lords of Rotenfluh (Unspunnen) and later given to the Freiherr of Weissenau, or it could have been established directly by the Weissenau family to serve as the center of their estates.

Strategically built on what was once an island at the mouth of the Aare River as it entered Lake Thun, the castle served as a significant stronghold. Over centuries, the island merged with the mainland due to silting, making the castle more accessible. The nearby market town of Widen flourished across the channel, connected to the castle by a bridge in 1362. In 1334, the Weissenau family's fortunes crumbled after a failed war against Bern, leaving them bankrupt and forced to sell the castle and Widen to Interlaken Abbey.

Widen's decline began in 1365 when the Abbey moved the markets and fair to Aarmühle (now Interlaken), stripping Widen of its economic base. By 1528, the Protestant Reformation reached the area, and Bern imposed the new faith, defeating Interlaken Abbey and secularizing its lands, including Weissenau Castle. The castle used as a prison until the 16th century, fell into ruin despite proposed restorations in 1655 and 1700 that were never carried out.

Today, Weissenau Castle stands as a ruin, with remnants of the residence, tower, and portions of the curtain wall still visible. These evocative remains offer a glimpse into the region's medieval past and its complex history of power struggles and shifting allegiances.