Louis III de Cossonay

Louis III de Cossonay, son of Louis I de Cossonay and Isabelle de Grandson, held Berchier as his appanage. A trusted servant of Amadeus VI, he executed his will in 1383 and served Amadeus VII as lieutenant-general and governor of Savoy in 1384.

When his nephew Louis II died in 1383, he inherited Cossonay. In 1391 he was made an adviser during Amadeus VIII's minority. He died in 1394 or 1395, the last male of his line, leaving his great-nieces as heirs.