Beginning in 982 the Sargans region was part of the lands of the Counts of Bregenz. In 1160, the male line of the Counts of Bregenz died out. Count palatine Hugo of Türbingen inherited most of their lands, through his wife Elisabeth. His son, Hugo, inherited the Bregenz lands around Lake Constance, including Sargans. This Hugo, who adopted the name Montfort und Werdenberg built or expanded Sargans Castle before his death in 1228. Excavations around the oldest part of the castle show that there was an earlier fort or castle, but nothing is known about that building. Hugo built the large bergfried, expanded the walls to the west and may have built a palas on that side of the castle.
In the mid-13th century the Montfort und Werdenberg lands were divided between Hugo of Werdenberg-Heiligenberg and his brother Hartmann of Werdenberg-Sargans. Hartmann took up residence in the castle and probably expanded the palas. The castle was first mentioned in 1282. Over the following century the wealth and lands of the Counts of Werdenberg-Sargans were divided over and over again between descendants. By the last 14th century, Count Johann I ruled over a small and poor county under the Habsburgs. In the Battle of Näfels in 1388, the count commanded a wing of the Austrian army that was supposed to cross the Kerenzerberg Pass. However, when he saw the threatened destruction of the main Austrian army, he fled back over the pass. The cost of the war, as well as other expenses forced Johann I to sell the castle and village to Leopold of Austria.
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.