Henry III, Duke of Brunswick-Grubenhagen Duke of Brunswick-Lüneburg and Prince of Grubenhagen (1416–1464) Parents Elisabeth of Brunswick-Göttingen Eric I, Duke of Brunswick-Grubenhagen Children Henry IV, Duke of Brunswick-Grubenhagen Otto von Braunschweig-Grubenhagen Siblings Margaret of Brunswick-Grubenhagen Anna of Brunswick-Grubenhagen-Einbeck Ernest II, Duke of Brunswick-Grubenhagen Albert II, Duke of Brunswick-Grubenhagen Elisabeth of Brunswick-Grubenhagen Agnes of Brunswick-Grubenhagen Sophie von Braunschweig-Grubenhagen Partners Margaret von Schlesien-Sagen