Frederick VII of Denmark
Following the death of King Frederick VII of Denmark (House of Oldenburg) in 1863, the inheritance of Schleswig and Holstein was disputed. The new king, Christian IX (House of Schleswig-Holstein-Sonderburg-Glücksburg, a cadet branch of the House of Oldenburg), made his claim to the Danish throne through a female line. The Duke of Augustenborg, a minor scion from another cadet line of the House of Oldenburg, claimed the Duchies, and soon the German Confederation, led by Prussia and Austria, went to the Second Schleswig War with Denmark, quickly defeating it in 1864 and forcing it to cede the duchies.