Return of the ducal family Duke Karl , a brother of King Christian IX, used the palace again as a permanent residence from 1871. When he moved in, he and his wife Wilhelmine were welcomed by the Friedrichsgarde. Since then, the castle has remained in the possession of the Glücksburg family and was inhabited by the family and relatives at almost all times. The following resided here as descendants of Duke Karl († 1863): Friedrich (Schleswig-Holstein-Sonderburg-Glücksburg), † 1885 Friedrich Ferdinand (Schleswig-Holstein-Sonderburg-Glücksburg), † 1934 One of the most famous regular guests was Auguste Viktoria, the last German Empress, who came from the closely related house of Schleswig-Holstein-Sonderburg-Augustenburg . Auguste Viktoria stayed at Glücksburg frequently, because her sister Caroline Mathilde was married to Friedrich Ferdinand and Auguste Viktoria visited her often. A series of rooms on the first floor are named after the Empress. Even Wilhelm II was a frequent guest, but rarely spent the night, instead sleeping on his yacht during his stays. From 1907 to 1910, Wilhelm II had the Mürwik Naval School built in the neighboring Mürwik. The School, built for the Imperial Navy, was nicknamed the Red Castle and was based on the model of the Malbork Castle. Glücksburg Castle remained the main residence of the ducal family until the 20th century. Only gradually did the family move to the mansions of the surrounding estates, such as Louisenlund or Grünholz. World wars The structures of the Glücksburg Castle made it through the world wars without suffering any substantial damages. Only the castle's bells were seized and melted down during World War I. Towards the end of World War II, under the Doenitz administration, Germany moved the seat of Government to Mürwik in the city of Flensburg. During this period, Albert Speer resided inside the castle. Here he was arrested by the allied forces on May 23, 1945, and brought to Flensburg. Until the summer of 1945, the castle was used as a prison for 200 former members of the Wehrmacht. In May 1945, British troops looted the castle, and took numerous valuables, many of which were later returned. Furthermore, 32 caskets in the tomb had been opened. While the looting took place, British troops detained the family of Friedrich Ferdinand zu Schleswig-Holstein-Sonderburg-Glücksburg at gunpoint. The return of the looted items followed a proclamation by the Queen of England, who is the niece of Friedrich Ferdinanfd. The reopening of