From Frederick VII. to Christoph Prinz
After 1854 the castle served as the summer residence for King Friedrich VII, who died here on 15 November 1863. In 1864/1865 Prussian troops used the castle as quarters and as a military hospital. As a consequence of the German-Danish War of 1864, Denmark ceded the dukedom of Schleswig-Holstein to the Prussian crown. King Wilhelm gave the castle back to the family, and in 1871 Duke Karl, the then head of the House of Schleswig-Holstein-Sonderburg-Glücksburg, resided in the castle. Karl was the brother of Christian IX, who, in 1846, withdrew from the Danish state service because of his opposition to the policy of the "Eiderdänen" who favoured a total merger of Schleswig with Denmark.
The last German Empress, Auguste Victoria (1858-1921), a descendant of the House of Schleswig-Holstein-Sonderburg-Augustenburg, stayed in Glücksburg frequently. Her sister Caroline Mathilde married Duke Friedrich Ferdinand (1855-1934). Hence, the last German Empress Auguste Victoria is the great-grand-aunt of the current head of the house, Christoph Prince of Schleswig-Holstein, and Caroline Mathilde, the Empress’s sister, is his great-grandmother.