The House of Schleswig-Holstein-Sonderburg-Glücksburg (Danish: Slesvig-Holsten-Sønderborg-Lyksborg, the latter name is also spelled Glücksborg), known as the House of Glücksburg (or House of Glücksborg) for short, is a German ducal house, junior branches of which include the royal houses of Denmark and Norway, the deposed royal house of Greece, and the heir to the thrones of the Commonwealth realms (although in the latter case, they are, by royal proclamation, declared to be members of the House of Windsor). The family is named after Glücksburg in northernmost Germany, and is a cadet branch of the House of Oldenburg that is descended from King Christian III of Denmark. However, as the elder line of the House of Oldenburg and the line of the House of Schleswig-Holstein-Sonderburg-Augustenburg became extinct in 1863 and 1931, respectively, the House of Glücksburg is now the senior surviving branch of the House of Oldenburg.

This particular line comes from the Dukes of Schleswig-Holstein-Sonderburg-Beck. The last of them became Duke of Glücksburg and changed his title accordingly to Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg. He was married to Princess Louise Caroline of Hesse-Kassel, a granddaughter of King Frederick V of Denmark.

Prince Philip, Duke of Edinburgh (born Prince Philip of Greece and Denmark 10 June 1921) is the husband of Elizabeth II. He is the United Kingdom's longest-serving consort and the oldest serving spouse of a reigning British monarch.

A member of the Danish-German House of Schleswig-Holstein-Sonderburg-Glücksburg, Prince Philip was born into the Greek royal family, but his family was exiled from Greece when he was a child. After being educated in Germany, England and Scotland, he joined the British Royal Navy at the age of 18 in 1939. From July 1939, he began corresponding with Princess Elizabeth, the eldest daughter and heiress presumptive of King George VI. During World War II he served with the Mediterranean and Pacific fleets.

After the war, Philip was granted permission by George VI to marry Elizabeth. Prior to the official engagement announcement, he renounced his Greek and Danish royal titles, converted from Greek Orthodoxy to Anglicanism, and became a naturalised British subject, adopting the surname Mountbatten from his British maternal grandparents. After an official engagement of five months, as Lieutenant Philip Mountbatten he married Elizabeth on 20 November 1947. On his marriage, he was granted the style of His Royal Highness and the title of Duke of Edinburgh by his father-in-law. Philip left active service, having reached the rank of Commander, when Elizabeth became Queen in 1952. His wife made him a Prince of the United Kingdom in 1957 and Lord High Admiral in 2011.

Harald V (born 21 February 1937) is the King of Norway. He succeeded to the throne of Norway upon the death of his father Olaf V on 17 January 1991. The son of the then-Crown Prince Olaf and of Princess Märtha of Sweden, Harald was born at the Crown Prince Residence at Skaugum, Akershus, Norway.

A member of the House of Schleswig-Holstein-Sonderburg-Glücksburg, originally from Northern Germany, Harald became the first Norwegian-born prince since Olaf IV, who was born in 1370. Harald V is the formal head of the Church of Norway and the Norwegian Armed Forces. He has two children, Crown Prince Haakon and Princess Märtha Louise. His grandchildren are Maud Angelica (2003), Leah Isadora (2005), Emma Tallulah (2008), Princess Ingrid Alexandra (2004), and Prince Sverre Magnus (2005).

Harald has two older sisters: Princess Ragnhild of Norway, Mrs. Lorentzen (Ragnhild Alexandra, born Oslo, 9 June 1930), who lives in Brazil, and Princess Astrid of Norway, Mrs. Ferner (Astrid Maud Ingeborg, born Oslo, 12 February 1932), who lives in Oslo.

Olav V (Alexander Edward Christian Frederik; 2 July 1903 – 17 January 1991) was the King of Norway from 1957 until his death. A member of the House of Schleswig-Holstein-Sonderburg-Glücksburg, Olav was born in the United Kingdom as the son of King Haakon VII of Norway and Queen Maud of Norway.

He became Crown Prince and heir-apparent to the throne of Norway when his father was elected king in 1905. He was the first heir to the Norwegian throne to be brought up in Norway since Olav IV, and his parents made sure he was given as Norwegian an upbringing as possible. In preparation for his royal duties, he attended both civilian and military schools. In 1929, he married his first and second cousin Princess Märtha of Sweden. During World War II his leadership was much appreciated and he was appointed Norwegian Chief of Defence in 1944. At his death, he was the last surviving grandchild of Edward VII of the United Kingdom and Alexandra of Denmark.

Due to his considerate, down-to-earth style, King Olav was immensely popular, resulting in the nickname Folkekongen ("People's King"). In a 2005 poll by the Norwegian Broadcasting Corporation, Olav was voted "Norwegian of the century".

Princess Dagmar of Denmark and Iceland (Dagmar Louise Elisabeth; 23 May 1890 – 11 October 1961) was the youngest child and fourth daughter of Frederick VIII of Denmark and his wife, Princess Louise of Sweden and Norway.

Princess Dagmar was born at Charlottenlund She was named for her aunt, the Empress Maria Fydorovna, who was born Princess Dagmar of Denmark.

She married in Fredensborg on 23 November 1922 Jørgen Castenskjold (Copenhagen, 30 November 1893 – Rungsted, 21 November 1978), son of Anton Castenskiold (1860–1940), Royal Danish Court Chamberlain, and wife Sophie Steensen-Leth (1870–1947), from Danish Nobility. They had four children:

Princess Dagmar died at Kongstedlund.