Rudolph Augustus, Duke of Braunschweig-Wolfenbüttel
Rudolph Augustus( May 16, 1627 – January 26, 1704), a member of the House of Welf, was Duke of Brunswick- Lüneburg and ruled as Prince of Brunswick- Wolfenbüttel from 1666 until his death.
In 1685 he made his younger brother Anthony Ulrich co-ruler.
Duke Anthony Ulrich of Brunswick
Anthony Ulrich (28 August 1714, Bevern – 4 May 1774
(O.S.), Kholmogory), Duke of Brunswick-Lüneburg, was generalissimus of the Army of Russia, and the husband of Anna Leopoldovna, who reigned as regent of Russia for one year.
Duke Louis Ernest of Brunswick-Lüneburg
Louis Ernest of Brunswick- Lüneburg- Bevern( 25 September 1718, Wolfenbüttel – 12 May 1788, Eisenach) was a field- marshal in the armies of the Holy Roman Empire and the Dutch Republic, the elected Duke of Courland( 1741).
From 13 November 1750 to 1766 he was the Captain- General of the Netherlands, where he was known as the Duke of Brunswick or( to distinguish him from his eldest brother Charles, who succeeded to their father's title of Duke of Brunswick- Lüneburg) Duke of Brunswick- Wolfenbüttel.
Another brother was Duke Ferdinand of Brunswick who led the Allied Anglo- German army during the Seven Years' War.
He was probably one of the first victims of the media in Dutch history.
Anna of Brunswick-Grubenhagen-Einbeck
Anna of Brunswick- Grubenhagen- Einbeck( 1414 – 4 April 1474) was a daughter of Duke Eric I of Brunswick- Grubenhagen and his wife, Elisabeth of Brunswick- Göttingen.
Anna's first marriage was with Duke Albert III of Bavaria.
They had the following children:
After Albert's death, she married Duke Frederick III of Brunswick- Calenberg- Göttingen.
This marriage remained childless.
Catherine Antonovna of Brunswick
Catherine Antonovna of Brunswick- Lüneburg( 1741–1807) was the daughter of Duke Anthony Ulrich of Brunswick and Grand Duchess Anna Leopoldovna of Russia and sister of Ivan VI.
She was imprisoned by Empress Elizabeth of Russia along with her family from 1742 to 1780 at Kholmogory, and in 1780, she and two brothers and a sister were placed under house arrest for the rest of their lives in Horsens.
She was the last descendant of Ivan V of Russia.
She became deaf after being dropped during the chaos of Empress Elizabeth's coup, and like her siblings, was sickly and suffered from bouts of seizures for much of her life.
She and her three surviving siblings were released into the custody of their aunt, the Danish queen dowager Juliana Maria of Brunswick- Wolfenbüttel, on 30 June 1780, and settled in Jutland.
There they lived under house arrest in Horsens for the rest of their lives under the guardianship of Juliana and at the expense of Catherine.
Although they were prisoners, they lived in relative comfort and retained a small" court" of between 40 and 50 people, all Danish except for the priest.
By 1798, Catherine lived alone in Horsens, since all her siblings had died.
In 1803, she wrote a letter to Alexander I of Russia: she told him how her Danish servants took advantage of her difficulty in hearing and talking, described how much she had missed the Russian prison in Kholmogory, where she and her siblings had been happy together, and asked him to be allowed to return.
He never replied.
Augusta Dorothea of Brunswick-Wolfenbüttel
Augusta Dorothea of Brunswick- Wolfenbüttel( 16 December 1666 in Wolfenbüttel – 11 July 1751 at Augustenburg Castle in Arnstadt) was a daughter of the Duke Anthony Ulrich of Brunswick- Wolfenbüttel and his wife Juliane of Holstein- Norburg.
Elizabeth Antonovna of Brunswick
Elizabeth Antonovna of Brunswick- Lüneburg( 1743 – 1782) was the daughter of Duke Anthony Ulrich of Brunswick and Grand Duchess Anna Leopoldovna of Russia.
Born after the deposition of her brother Ivan VI, she was kept imprisoned by Empress Elizabeth of Russia along with her family at Kholmogory, and in 1780, she and two brothers and a sister were placed under house arrest for the rest of their lives in Horsens.
Elisabeth Eleonore of Brunswick-Wolfenbüttel
Elisabeth Eleonore of Brunswick- Wolfenbüttel( 30 September 1658, in Wolfenbüttel – 15 March 1729, in Meiningen) was the eldest daughter of Duke Anthony Ulrich of Brunswick- Wolfenbüttel and his wife Juliane of Schleswig- Holstein- Sonderburg- Norburg.
Ekaterina Chernysheva
Ekaterina Chernysheva( 1715-1779) was a Russian courtier.
She was the daughter of Andrey Ushakov and married the diplomat count Peter Chernyshev, Russian ambassador to Denmark, Prussia, England and France, and was the mother of Darya Petrovna Saltykova and Natalya Golitsyna.
From 1730 until her marriage in 1738, she served as maid of honour to Anna of Russia.
She was a favorite and confidante of Anna Leopoldovna, which resulted in a demand from the powerful favorite Ernst Johann von Biron that she persuade Anna to refuse a marriage to Duke Anthony Ulrich of Brunswick in favor of Peter von Biron, a task she unsuccessfully tried to achieve.
Anna Leopoldovna
Anna Leopoldovna (18 December 1718 – 19 March 1746), born Elisabeth Katharina Christine von Mecklenburg-Schwerin and also known as Anna Carlovna (А́нна Ка́рловна), was regent of Russia for a few months in 1740 and 1741 during the minority of her infant son Emperor Ivan VI.

Question: When did Duke Anthony Ulrich Of Brunswick's wife die?
Answer: 19 March 1746