"The Swiss, or more precisely, the Bernese, conquered the Pays de Vaud. The conquest was completed once the Bernese took-over the Chillon Castle in 1536. For more than 260 years, the castle retained its role as a fortress, arsenal, and prison.
After a three-week siege, the Bernese finally entered the fortress. On March 29th, 1536, their conquest of the Pays de Vaud was completed as they took over the castle of Chillon. The Bernese divided the Pays de Vaud into twelve bailliages, and Chillon became the administrative center for the bailliage of Vevey.
Under the Counts of Savoy, the castle was divided into two parts, one for the castellan bailiff, and the other for the Counts, when they resided at Chillon. This division was no longer useful, and the Bernese took possession of all the space in the castle. Concerning the defensive aspects, the fortress was adapted to the then new firearms.
In 1733, the bailiffs left the castle, which had become isolated and uncomfortable, and moved on to a more modern residence in Vevey." www.chillon.ch