Joachim Frederick, Duke of Schleswig-Holstein-Sonderburg-Plön
Joachim Frederick of Schleswig-Holstein- Sonderburg- Plön( 9 May 1668, Magdeburg – 25 January 1722, Plön), also known as Joachim Frederick of Schleswig- Holstein- Plön, was the third Duke of Schleswig- Holstein- Plön, a dukedom created by the division of the Duchy of Schleswig- Holstein- Sonderburg.
Augustus, Duke of Schleswig-Holstein-Sonderburg-Plön-Norburg
Duke Augustus of Schleswig-Holstein-Sonderburg-Plön-Norburg (9 May 1635 – 17 September 1699 in Plön) was Duke of a small part of Schleswig-Holstein around Nordborg Castle on the island of Als.
He was the founder of the Schleswig-Holstein-Sonderburg-Plön-Norburg line.
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.
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.
Louise Albertine of Schleswig-Holstein-Sonderburg-Plön
Louise Albertine, Princess of Anhalt-Bernburg (née Princess Louise Albertine of Schleswig-Holstein-Sonderburg-Plön; 21 July 1748 – 2 March 1769) was a member of the Danish royal family and the consort of Frederick Albert, Prince of Anhalt-Bernburg.
Frederick Albert, Prince of Anhalt-Bernburg
Frederick Albert of Anhalt-Bernburg (15 August 1735 – 9 April 1796), was a German prince of the House of Ascania and Reigning prince of the principality of Anhalt-Bernburg from 1765 to 1796.
Joachim Ernest, Duke of Schleswig-Holstein-Sonderburg-Plön
Joachim Ernest of Schleswig-Holstein- Sonderburg- Plön( 29 August 1595 – October 5, 1671), also" Joachim Ernest of Schleswig- Holstein- Plön", was the first Duke of Schleswig- Holstein- Sonderburg- Plön, which emerged from a division of the Duchy of Schleswig- Holstein- Sonderburg.
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.
John Adolphus, Duke of Schleswig-Holstein-Sonderburg-Plön
John Adolphus of Schleswig- Holstein- Sonderburg- Plön( or" Hans Adolf"; 8 April 1634, Ahrensbök – 2 July 1704 Ruhleben) was the second Duke of Schleswig- Holstein- Sonderburg- Plön, which had been created by a division of the Duchy of Schleswig- Holstein- Sonderburg.
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.

Question: When did Louise Albertine Of Schleswig-Holstein-Sonderburg-Plön's husband die?
Answer: 9 April 1796