Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg
Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg (4 January 1785 – 17 February 1831) inherited the title of Duke of Schleswig-Holstein-Sonderburg-Beck in 1816.
He subsequently changed his title to Duke of Schleswig-Holstein-Sonderburg-Glücksburg in 1825 and founded a line that includes the Royal Houses of Denmark, Greece, Norway, and the Commonwealth realms.
Prince Julius of Schleswig-Holstein-Sonderburg-Glücksburg
Prince Julius of Schleswig-Holstein- Sonderburg- Glücksburg( 14 October 1824, Gottorp, Schleswig, Duchy of Schleswig – 1 June 1903, Itzehoe, Schleswig- Holstein, Germany) was the eighth of the ten children of Friedrich Wilhelm, Duke of Schleswig- Holstein- Sonderburg- Glücksburg and Princess Louise Caroline of Hesse- Kassel.
Friedrich Ferdinand, Duke of Schleswig-Holstein
Friedrich Ferdinand of Schleswig- Holstein- Sonderburg- Glücksburg( 12 October 1855 – 21 January 1934) was the fourth Duke of Schleswig- Holstein- Sonderburg- Glücksburg and became Duke of Schleswig- Holstein in 1931.
Friedrich, Duke of Schleswig-Holstein-Sonderburg-Glücksburg
Friedrich of Schleswig- Holstein- Sonderburg- Glücksburg( 23 October 1814 in Schleswig, Duchy of Schleswig – 27 November 1885 in Luisenlund, Schleswig- Holstein, Prussia) was the third Duke of Schleswig- Holstein- Sonderburg- Glücksburg.
Friedrich was the second- eldest son of Friedrich Wilhelm, Duke of Schleswig- Holstein- Sonderburg- Glücksburg and Princess Louise Caroline of Hesse- Kassel and an elder brother of Christian IX of Denmark.
Friedrich inherited the title of Duke of Schleswig- Holstein- Sonderburg- Glücksburg upon his childless brother Karl's death on 14 October 1878.
Princess Alexandra Victoria of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Alexandra Victoria of Schleswig-Holstein- Sonderburg- Glücksburg( 21 April 1887 – 15 April 1957) was a daughter of Friedrich Ferdinand, Duke of Schleswig- Holstein and his wife Princess Karoline Mathilde of Schleswig- Holstein- Sonderburg- Augustenburg.
Karl, Duke of Schleswig-Holstein-Sonderburg-Glücksburg
Karl of Schleswig-Holstein-Sonderburg-Glücksburg (30 September 1813 at Gottorp in Schleswig, Duchy of Schleswig – 24 October 1878 at Luisenlund, Glücksburg, in Schleswig-Holstein, Prussia) was the second Duke of Schleswig-Holstein-Sonderburg-Glücksburg.
Karl was the eldest son of Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg and Princess Louise Caroline of Hesse-Kassel and an elder brother of Christian IX of Denmark.
Karl became Duke of Schleswig-Holstein-Sonderburg-Glücksburg upon his father's death on 27 February 1831.
Princess Helena Adelaide of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Helena Adelaide of Schleswig-Holstein- Sonderburg- Glücksburg( 1 June 1888- 30 June 1962) was the third eldest daughter of Friedrich Ferdinand, Duke of Schleswig- Holstein and his wife Princess Karoline Mathilde of Schleswig- Holstein- Sonderburg- Augustenburg.
She was a princess of Denmark through her marriage within the House of Schleswig- Holstein- Sonderburg- Glücksburg to Prince Harald of Denmark.
Princess Helena was a Nazi sympathiser during World War II and was after the war exiled from Denmark, but eventually allowed to return, where she died.
Augusta of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Augusta of Schleswig-Holstein- Sonderburg- Glücksburg( 27 June 1633 – 26 May 1701) was a Danish- German princess of the senior Glücksburg line of the Duke of Schleswig- Holstein.
She was the first Duchess of Augustenborg by marriage.
Augustenborg palace, and as a consequence the nearby town, were named in honor of her.
The great- granddaughter of king Christian III of Denmark, she was the third daughter, eighth by birth, of Philip, Duke of Schleswig- Holstein- Sonderburg- Glücksburg and Princess Sophia Hedwig of Saxe- Lauenburg.
She was sister of Sophia Dorothea of Schleswig- Holstein- Sonderburg- Glücksburg
Wilhelm Friedrich, Duke of Schleswig-Holstein
Friedrich, Duke of Schleswig- Holstein- Sonderburg- Glücksburg, from 1934 Duke of Schleswig- Holstein( 23 August 1891 – 10 February 1965), was the Duke of Schleswig- Holstein and Head of the House of Oldenburg from 21 January 1934 until his death on 10 February 1965.
Princess Karoline Mathilde of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Karoline Mathilde of Schleswig- Holstein- Sonderburg- Glücksburg( Viktoria- Irene Adelheid Auguste Alberta Feodora Karoline Mathilde of Schleswig -Holstein- Sonderburg- Glücksburg; 11 May 1894 – 28 January 1972) was a member of the House of Schleswig- Holstein- Sonderburg- Glücksburg and Princess of Schleswig- Holstein- Sonderburg- Glücksburg by birth and a member of the House of Solms Baruth and Countess of Solms Baruth through her marriage to Count Hans of Solms- Baruth.

Question: When did Karl, Duke Of Schleswig-Holstein-Sonderburg-Glücksburg's father die?
Answer: 17 February 1831