Question of the Dauphiné and the Piedmont
In 1343 Louis was tasked with presenting Savoyard fears about the agreed upon sale of the Dauphiné to Philip, Duke of Orléans, a younger son of the French king, to the chancellor of France. Nothing seems to have come of Louis's diplomacy, but he and fellow regent Amadeus III had been reconciled to the plan by January 1344, when they agreed to a marriage between their youthful charge and Joan, a daughter of Peter I, Duke of Bourbon, and thus a grand-niece of the French king.
In 1347 Louis again tried to block the French acquisition of the Dauphiné. When the reigning dauphin, Humbert II, returned from his Smyrniote crusade a widower in the spring, Pope Clement VI, who formerly favoured the French, encouraged him to remarry and sire an heir. The papal change of mind was probably induced by the several embassies which Louis can be shown to have sent to the papal court at Avignon during the year, from surviving treasury accounts. In May Louis was preparing to once again lead an army to the aid of France, in obedience to a summons, when he received word that his cousin James, Lord of Piedmont, was threatened by an alliance of the Visconti of Milan, former relatives by marriage of Louis's, and Marquis John II of Montferrat. The lord of Piedmont held extensive lands in the Canavese, of which Louis was lieutenant-general. Before leaving for France, Louis sent the marshal of Savoy, Antelme de Miolans, to the Piedmont with an army. After his return Louis took the cases of the Dauphiné and the Piedmont to the papal court, where he stayed through the winter of 1347–48.
"After sixty years of active and adventurous life", Louis died late in 1348 or early the next year, certainly before 29 January 1349, possibly of the Black Death then sweeping Europe. He was succeeded by his daughter Catherine, who, twice widowed, ruled for two years jointly with her mother. The two were known as les Dames de Vaud, the ladies of Vaud.
