Duchy of Brunswick-Lüneburg
The Principality of Grubenhagen was a subdivision of the Duchy of Brunswick-Lüneburg, ruled by the Grubenhagen line of the House of Welf from 1291. It is also known as Brunswick-Grubenhagen. The principality fell to the Brunswick Principality of Lüneburg in 1617; from 1665 the territory was ruled by the Calenberg branch of the Welf dynasty.