The kings of Denmark, members of the House of Oldenburg, held the Duchy of Lauenburg from 1815 to 1864, when the territory came under Prussian control as a result of the Second Schleswig War, though it was not immediately annexed to Prussia.
The Danish royal family, members of the House of Oldenburg, oversaw the Duchy of Lauenburg from 1815 to 1864. The territory then passed into Prussian control following the Second Schleswig War, although it was not immediately merged with Prussia.