The lords of Aarwangen were first mentioned between 1194 and 1212 as a Ministerialis (unfree knights in the service of a feudal overlord) family in service to the Kyburgs. Starting in 1266, Walter of Aarwangen was in the service of the future King of the Romans Rudolph I. Initially they owned land in the Emmental, but in 1276 they sold the land to Trub monastery. Around 1300 they built the tower of Aarwangen Castle along the banks of the Aar river. In 1313, they were firmly established in Aarwangen when Rudolf III of Neuenburg-Nidau granted them the bridge over the Aar river as a fief. After Walter's death in 1320, his son Johann took over the castle and leadership of the family. Johann was a patron of the Cistercian Abbey of St. Urban in Hasle, Lucerne and in 1341 he joined the Abbey. He remained at the Abbey until his death in 1350, which ended the Aarwangen noble line.
After the Aarwangen family died out, the castle went to the Grünenberg family. They sold it in 1432 to the city of Bern. It served as the seat of the Bernese bailiff until 1798. It is now the administrative seat of the surrounding district.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.