Albert I, Duke of Brunswick-Grubenhagen Duke of the Principality of Grubenhagen (1339–1383) Parents Adelheid of Brunswick-Grubenhagen Ernest I, Duke of Brunswick-Grubenhagen Children Eric I, Duke of Brunswick-Grubenhagen Siblings Frederick I, Duke of Brunswick-Osterode John II of Brunswick-Grubenhagen Anna von Osterode Adelheid von Osterode Otto von Osterode Anna II. von Osterode Agnes von Osterode Ernst von Braunschweig-Grubenhagen Partners Agnes of Brunswick-Lüneburg