structural:summarization, structural:expansion
The Duchy of Savoy was a territorial entity of the Savoyard state that existed from 1416 until 1847 and was a possession of the House of Savoy. It was created when Sigismund, Holy Roman Emperor, raised the County of Savoy into a duchy for Amadeus VIII. The duchy was an Imperial fief, subject of the Holy Roman Empire, until 1792, with a vote in the Imperial Diet. From the 16th century, Savoy belonged to the Upper Rhenish Circle. Its territory included the current French departments of Savoie, Haute-Savoie, and the Alpes-Maritimes, the current Italian region of Aosta Valley, a large part of Piedmont and the County of Geneva in Switzerland, which was then lost to the Old Swiss Confederacy. The main Vulgar languages that were spoken within the Duchy of Savoy were Piedmontese and Arpitan.