House of Glücksburg
The Danish line of Oldenburg kings died out in 1863, and the elder line of the Schleswig-Holstein family became extinct with the death of the last Augustenburg duke in 1931. Thereafter, the House of Glücksburg became the senior surviving line of the House of Oldenburg. Another cadet line of Oldenburgs, the Dukes of Holstein-Gottorp, consisted of two branches which held onto sovereignty into the 20th century. But members of the Romanov line were executed in or exiled from their Russian Empire in 1917, while the Grand Duchy of Oldenburg was abolished in 1918, although its dynastic line survives.