After the Bernese victory in the Battle of Laupen in 1339, the barons were forced to pledge the Unspunnen and Rotenfluh castles as part of the peace settlement. A few years later, in 1342, the Habsburgs redeemed this pledge and then pledged it on to their followers, including the lords of Interlaken, Hallwyl and Kyburg. During the Battle of Sempach in 1386, Bern occupied the area and in 1397 paid off the mortgage. In the next year they sold the castle and lands to the von Seftigen and von Scharnachtal families, who were citizens of Bern. In 1418 and again in 1515, Bern bought the lands back from the families' heirs. Bern placed the Unspunnen lands directly under the city's authority in 1529. In 1762 the lands were transferred to the administration of Interlaken and the castle was allowed to fall into disrepair. The ruins became famous through the Unspunnenfest in 1805 which led to regular cleaning and repairs of the ruins.