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.
Grand Duchess Catherine Mikhailovna of Russia
Grand Duchess Catherine Mikhailovna of Russia( 28 August 1827 – 12 May 1894), was the third of five daughters of Grand Duke Michael Pavlovich of Russia( youngest son of Emperor Paul I and Princess Sophie Dorothea of Württemberg) and Princess Charlotte of Württemberg( eldest child of Prince Paul of Württemberg and Princess Charlotte of Saxe- Hildburghausen).
Catherine Pavlovna of Russia
Grand Duchess Catherine Pavlovna of Russia( 21 May 1788[ OS 10 May 1788] – 9 January 1819) later Queen Catharina Pavlovna of Württemberg, was the fourth daughter of Tsar Paul I of Russia and Duchess Sophie Dorothea of Württemberg.
She became the Queen of Württemberg upon her marriage to her first cousin Crown Prince William who eventually became King William I of Württemberg in 1816.
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.
Duchess Augusta of Brunswick-Wolfenbüttel
Duchess Augusta of Brunswick-Wolfenbüttel (Augusta Caroline Friederika Luise; 3 December 1764 – 27 September 1788)<ref name="Birth/death details"></ref
> was the first wife of Frederick of Württemberg and the mother of William I of Württemberg.
Like her sister, Caroline of Brunswick, Augusta had a scandalous personal life and an unhappy marriage.
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.
Prince Paul of Württemberg
Prince Paul of Württemberg
(Paul Heinrich Karl Friedrich August; 19 January 1785 – 16 April 1852) was the fourth child and second son of King Frederick I and his wife, Duchess Augusta of Brunswick-Wolfenbüttel.
Through an illegitimate daughter, Paul is the great-great-great-great-grandfather of British Prime Minister Boris Johnson.
Christoph, Duke of Württemberg
Christoph of Württemberg, Duke of Württemberg (12 May 1515 – 28 December 1568) ruled as Duke of Württemberg from 1550 until his death in 1568.
Princess Augusta of Württemberg
Princess Augusta of Württemberg( 4 October 1826 in Stuttgart – 3 December 1898, ibid.) was a daughter of King William I of Württemberg and his wife, Pauline 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.

Question: When did Prince Paul Of Württemberg's mother die?
Answer: 27 September 1788