The Dukes of Savoy had tried already for centuries to gain sovereignty over the city of Geneva, surrounded by Savoyard territory, for the Vaud in the north of Lake Geneva belonged to the duchy. The Reformation prompted the conflicts to escalate once more. Geneva exiled its bishop, who was backed by Savoy, in 1533 to Annecy. Bern and the Valais took advantage of the duke's involvement in northern Italy and his opposition to France. When Francesco II Sforza died in Milan in 1534, the duke's troops were bound by the French engagement there, and Bern promptly conquered the Vaud and, together with the Valais, also territories south of Lake Geneva in 1536.