Charlotte Christine of Brunswick-Wolfenbüttel
Charlotte Christine Sophie also known as Sophie Charlotte or simply Charlotte (28 August 1694, Wolfenbüttel – 2 November 1715, Saint Petersburg), was the wife of Tsarevich Alexei Petrovich of Russia.
She was the daughter of Louis Rudolph, Duke of Brunswick-Wolfenbüttel and Princess Christine Louise of Oettingen-Oettingen.
She was also the great aunt of Queen Marie Antoinette of France.
Matilda of Brunswick-Lüneburg
Matilda of Brunswick- Lüneburg( 1276 – 26 April 1318) was a German noblewoman and member of the House of Welf.
By birth, she was a duchess of Brunswick- Lüneburg and by marriage Duchess of Glogów, Ścinawa, etc.
She was the seventh child and only daughter of Albert I, Duke of Brunswick- Lüneburg by his second wife Alessina, daughter of Margrave Boniface II of Montferrat.
Henry the Peaceful, Duke of Brunswick-Lüneburg
Henry the Peaceful( 1411 – 7 December 1473), Duke of Brunswick- Lüneburg, called the Peaceful, ruled over both parts of Brunswick- Lüneburg.
Peter II of Russia
Peter II Alexeyevich( Russian: Пётр II Алексеевич," Pyotr II Alekseyevich") reigned as Emperor of Russia from 1727 until his untimely death.
He was the only son of Tsarevich Alexei Petrovich( son of Peter the Great by his first wife, Eudoxia Lopukhina) and of Charlotte Christine of Brunswick- Lüneburg.
Elizabeth of Denmark, Duchess of Brunswick-Wolfenbüttel
Elisabeth of Denmark (25 August 1573 – 19 July 1625) was duchess consort of Brunswick-Lüneburg as married to Duke Henry Julius of Brunswick-Lüneburg.
She was regent of Brunswick-Lüneburg in 1616-1622.
Dorothea of Brunswick-Lüneburg
Dorothea of Brunswick-Lüneburg (1 January 1570 – 15 August 1649) was a daughter of Duke William "the younger" of Brunswick-Lüneburg and his wife, Dorothea of Denmark, Duchess of Brunswick-Lüneburg.
She married Count Palatine Charles I of Zweibrücken-Birkenfeld.
They had four children:
Alexei Petrovich, Tsarevich of Russia
Alexei Petrovich of Russia (28 February 1690 – 7 July 1718) was a Russian Tsarevich.
He was born in Moscow, the son of Tsar Peter I and his first wife, Eudoxia Lopukhina.
Alexei despised his father and repeatedly thwarted Peter's plans to raise him as successor to the throne.
His brief defection to Austria scandalized the Russian government, leading to harsh repressions against Alexei and his associates.
Alexei died after interrogation under torture, and his son Peter Alexeyevich became the new heir apparent.
Francis Otto, Duke of Brunswick-Lüneburg
Francis Otto, Duke of Brunswick- Lüneburg( 1530 – 1559) was the Prince of Lüneburg from 1555 to 1559.
He was the son of Ernest I, Duke of Brunswick- Lüneburg.
Margaret of Brunswick-Lüneburg (1442–1512)
Margaret of Brunswick- Lüneburg( 1442 – 8 April 1512 in Wienhausen) was a princess of Brunswick- Lüneburg by birth and by marriage a Duchess of Mecklenburg- Stargard.
Juliana Luise von Ostfriesland
Juliana Luise von Ostfriesland( 1698- 1740), was Princess of Ostfriesland, a member of the House of Cirksena and by marriage Duchess of Schleswig- Holstein- Sonderburg- Plön.
As a first cousin of Charlotte Christine of Brunswick- Lüneburg, she was chosen to be her the Ober- Hofmeisterin at the Russian court.
A favorite and confidant of Charlotte Christine, she was accused of isolating her from Russia, prevented her from adjusting to her new life and creating distance between her and her spouse, the Russian heir to the throne.

Question: Who is Charlotte Christine Of Brunswick-Wolfenbüttel's mother-in-law?
Answer: Eudoxia Lopukhina