Adelaide of Brunswick-Lüneburg (1250-1274) (1250–1274) Parents Matilda of Brandenburg, Duchess of Brunswick-Lüneburg Otto the Child Children Sofie von Hessen Otto I, Landgrave of Hesse Adelheid Henry the Younger of Hesse Elisabeth von Hessen Mechthild von Hessen Siblings Mathilde of Brunswick-Lüneburg Albert I, Duke of Brunswick-Lüneburg Conrad of Brunswick-Luneburg Elisabeth of Brunswick-Lüneburg Helene of Brunswick-Lüneburg Bishop Otto I of Brunswick-Lüneburg John, Duke of Brunswick-Lüneburg Agnes of Brunswick-Lüneburg Partners Henry I, Landgrave of Hesse