Friedrich Franz, Hereditary Grand Duke of Mecklenburg-Schwerin
Friedrich Franz, Hereditary Grand Duke of Mecklenburg- Schwerin( 22 April 1910 – 31 July 2001) was the heir apparent to the throne of Mecklenburg- Schwerin and a member of the Waffen- SS.
Duchess Charlotte Frederica of Mecklenburg-Schwerin
Duchess Charlotte Frederica of Mecklenburg-Schwerin (4 December 1784 – 13 July 1840), was the first wife of King Christian VIII from 1806 until 1810, before he became King of Denmark.
She was a daughter of Frederick Francis I, Grand Duke of Mecklenburg-Schwerin, and Princess Louise of Saxe-Gotha-Altenburg, the seventh of the couple's surviving children born at Ludwigslust's court.
Christian VIII of Denmark
Christian VIII (18 September 1786 – 20 January 1848) was the King of Denmark from 1839 to 1848 and, as Christian Frederick, King of Norway in 1814.
Duke Louis of Mecklenburg-Schwerin
Duke Louis of Mecklenburg- Schwerin( 6 August 172512 September 1778) was heir to the Dukedom of Mecklenburg- Schwerin from 1756 to his death.
He was also the father of the first Grand Duke of Mecklenburg- Schwerin Frederick Francis I
Duchess Louise Charlotte of Mecklenburg-Schwerin
Duchess Louise Charlotte of Mecklenburg- Schwerin( 19 November 1779 – 4 January 1801) was the maternal grandmother of Prince Albert, husband of Queen Victoria of the United Kingdom.
Louise Charlotte was born Duchess of Mecklenburg- Schwerin, her father being Friedrich Franz I, Grand Duke of Mecklenburg- Schwerin.
Her mother was Princess Louise of Saxe- Gotha- Altenburg; her sister Charlotte of Mecklenburg- Schwerin( 1784–1840) married King Christian VIII of Denmark.
Christian Louis I, Duke of Mecklenburg
Christian Louis I, Duke of Mecklenburg- Schwerin( 1 December 1623 in Schwerin – 21 June 1692 in The Hague) was a reigning Duke of Mecklenburg- Schwerin.
Duchess Sophia Frederica of Mecklenburg-Schwerin
Sophia Frederica of Mecklenburg- Schwerin( 24 August 1758 – 29 November 1794) was a Princess and Duchess of Mecklenburg- Schwerin, and by marriage Hereditary Princess of Denmark and Norway.
Karin Elisabeth von Schaper
Karin Elisabeth, Hereditary Grand Duchess of Mecklenburg- Schwerin( née" von Schaper", Karin Elisabeth Henriette Lori Gudela; 31 January 1920 – 26 January 2012) was a member by marriage of the House of Mecklenburg- Schwerin.
She was the widow of Friedrich Franz, Hereditary Grand Duke of Mecklenburg- Schwerin.
Magnus II, Duke of Mecklenburg
Magnus II, Duke of Mecklenburg- Schwerin and Güstrow( 1441 – 20 November 1503) was duke of Mecklenburg- Schwerin from 1477 until his death.
Frederick Louis, Hereditary Grand Duke of Mecklenburg-Schwerin
Frederick Louis of Mecklenburg- Schwerin( 13 June 1778 – 29 November 1819) was a hereditary prince of the Grand Duchy of Mecklenburg- Schwerin, one of the constituent states of the German Confederation.
He was the son of Frederick Francis I, Grand Duke of Mecklenburg- Schwerin, and of Princess Louise of Saxe- Gotha- Altenburg.

Question: When did Duchess Charlotte Frederica Of Mecklenburg-Schwerin's husband die?
Answer: 20 January 1848