 He bequeathed the duchy to Duke William the Rich of Jülich-Cleves-Berg (also known as Wilhelm of Cleves).Following in the footsteps of Charles of Egmond, Duke William formed an alliance with France, an alliance dubiously cemented via his political marriage to French King Francis I's niece Jeanne d'Albret (who reportedly had to be whipped into submission to the marriage, and later bodily carried to the altar by the Constable of France, Anne de Montmorency).This alliance emboldened William to challenge Emperor Charles V's claim to Guelders, but the French, mightily engaged on multiple fronts as they were in the long struggle to against the Habsburg "encirclement" of France, proved less reliable than the Duke's ambitions required, and he was unable to hold on to the duchy; in 1543, by the terms of the Treaty of Venlo, Duke William conceded the Duchy of Guelders to the Emperor.