Prince Frederick of Württemberg
Prince" Frederick" Charles Augustus of Württemberg( 21 February 1808 – 9 May 1870) was a General in the Army of Württemberg and the father of William II of Württemberg.
Frederick was a member of the Royal Family of Württemberg and a Prince of Württemberg.
Princess Catherine of Württemberg
Princess Catherine Frederica Charlotte of Württemberg (Stuttgart, 24 August 1821 – Stuttgart, 6 December 1898) was a daughter of William I of Württemberg and Pauline Therese of Württemberg.
She was the mother of William II of Württemberg.
Duke Alexander of Württemberg (1804–1885)
Duke Alexander Paul Ludwig Konstantin of Württemberg (9 September 1804, Saint Petersburg – 4 July 1885 Tüffer) was the father of Francis, Duke of Teck and the grandfather of Mary of Teck, wife of George V of the United Kingdom.
His father was Duke Louis of Württemberg, brother of King Frederick I of Württemberg and Empress Maria Feodorovna of Russia.
His mother was Princess Henriette of Nassau-Weilburg, a great-granddaughter of George II of Great Britain through his eldest daughter Anne, Princess of Orange.
Duchess Marie of Württemberg
Duchess Marie of Württemberg (Antoinette Friederike Auguste Marie Anna Herzogin von Württemberg; 17 September 1799 – 24 September 1860) was a daughter of Duke Alexander of Württemberg and Antoinette of Saxe-Coburg-Saalfeld.
She was Duchess of Saxe-Coburg and Gotha from 1832 to 1844 as the second wife of Duke Ernest I.
As such, she was the stepmother of Prince Albert, consort of Queen Victoria.
Pauline Therese of Württemberg
Pauline of Württemberg (4 September 1800 – 10 March 1873) was a daughter of Duke Louis of Württemberg and Princess Henriette of Nassau-Weilburg.
She married her first cousin King William I of Württemberg and was his consort.
Duke Alexander of Württemberg (1771–1833)
Duke Alexander of Württemberg
(Mömpelgard/Montbéliard, then Württemberg (now France), 5 May 1771 – Gotha, Thuringia, Germany, 4 July 1833) was a Duke of Württemberg.
The son of Frederick II Eugene, Duke of Württemberg and of Sophia Dorothea of Brandenburg-Schwedt.
His sister Sophie Dorothea married Tsar Paul I of Russia.
Countess Claudine Rhédey von Kis-Rhéde
Countess Claudine Rhédey von Kis- Rhéde( baptised 21 September
1812 – 1 October 1841) was the Hungarian wife of Duke Alexander of Württemberg.
Her son, Francis, Duke of Teck, was the father of Mary of Teck, queen consort to George V of the United Kingdom.
Duke Alexander of Württemberg (1804–1881)
Duke Alexander of Württemberg( 20 December 1804 – 28 October 1881) was a member of the dynasty which ruled the German kingdom of Württemberg.
To marry a daughter of the French king he agreed that their children would be raised in their mother's faith, thereby becoming ancestor of the Roman Catholic branch of his family.
Duke Louis of Württemberg
Duke Louis of Württemberg ("Ludwig Friedrich Alexander")
(Treptow an der Rega, 30 August 1756 – Kirchheim unter Teck, 20 September 1817)
was the second son of Frederick II Eugene, Duke of Württemberg (1732–1797) and Margravine Sophia Dorothea of Brandenburg-Schwedt (1736–1798).
His elder brother was Frederick I, the first King of Württemberg, his sister was the Russian Empress consort, Maria Feodorovna.
Louis retained the pre-royal title of Duke.
Louis Frederick, Duke of Württemberg-Montbéliard
Louis Frederick of Württemberg- Montbéliard( 29 January 1586 in Montbéliard – 26 January 1631 in Montbéliard) was the founder of a cadet line of the House of Württemberg known as the Dukes of Württemberg- Montbéliard.
Louis Frederick of Württemberg was born at Montbéliard Castle as the fifth child and second son of Duke Frederick I of Württemberg, and princess Sibylla of Anhalt.

Question: What is the date of death of Duke Alexander Of Württemberg (1804–1885)'s father?
Answer: 20 September 1817