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.
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.
Princess Adelheid of Schaumburg-Lippe
Princess Adelheid of Schaumburg-Lippe (9 March 1821 in Bückeburg, Schaumburg-Lippe – 30 July 1899 in Itzehoe, Schleswig-Holstein, Germany) was a member of the House of Schaumburg-Lippe and a Princess of Schaumburg-Lippe by birth.
Through her marriage to Friedrich, Duke of Schleswig-Holstein-Sonderburg-Glücksburg, Adelheid was a sister-in-law of Christian IX of Denmark and Duchess consort of Schleswig-Holstein-Sonderburg-Glücksburg from 14 October 1878 to 27 November 1885.
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.
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.
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.
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 Louise of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Louise of Schleswig-Holstein-Sonderburg-Glücksburg (6 January 1858 in Schloss Luisenlund, Kiel, Duchy of Schleswig – 2 July 1936 in Marburg an der Lahn, Hesse, Germany) was the princess consort of George Victor, Prince of Waldeck and Pyrmont.
Louise was the third child and second eldest daughter of Friedrich, Duke of Schleswig-Holstein-Sonderburg-Glücksburg and Princess Adelheid of Schaumburg-Lippe and a niece of Christian IX of Denmark.
Princess Louise Caroline of Hesse-Kassel
Princess Louise Caroline of Hesse- Kassel( 28 September 1789 – 13 March 1867) was the consort of Friedrich Wilhelm, Duke of Schleswig- Holstein- Sonderburg- Glücksburg and the matriarch of the House of Schleswig- Holstein- Sonderburg- Glücksburg, which would eventually become the ruling house of the kingdoms of Denmark, Greece, Norway, and the United Kingdom.
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.

Question: When did Princess Louise Of Schleswig-Holstein-Sonderburg-Glücksburg's mother die?