Maria Thins
Maria Thins( c. 1593 – 27 December 1680) was the mother- in- law of Johannes Vermeer and a member of the Gouda Thins family.
Eldon Howard
Eldon Howard was a British screenwriter.
She was the mother- in- law of Edward J. Danziger and wrote a number of the screenplays for films by his company Danziger Productions.
Grimoald the Younger
Grimoald II  (died 714), called the Younger, was the mayor of the palace of Neustria from 695.
He was the second son of Pepin of Herstal and Plectrude and his father placed him in the office of mayor of the palace in the Neustrian kingdom in 695, when he was still young.
He married Theudesinda (or Theodelinda), daughter of Radbod, King of the Frisians, and had two sons: Theudoald and Arnold.
While en route to visit the tomb of Saint Lambert at Liège, he was assassinated by a certain Rangar, in the employ of his father-in-law.
His sons carried on a fight to be recognised as Pepin of Herstal's true heirs, since Grimoald predeceased his father and his half-brother Charles Martel usurped the lands and offices of their father.
In short, he was innocent but unlucky.
Marian Shields Robinson
Marian Lois Robinson( née Shields; born July 29, 1937) is the mother of Michelle Obama, former First Lady of the United States, and Craig Robinson, a basketball executive, and the mother- in- law of former U.S. President Barack Obama.
Priscilla Pointer
Priscilla Marie Pointer( born May 18, 1924) is an American stage, film and television character actress.
She began her career in the theater, including productions on Broadway.
Later, Pointer moved to Hollywood to act in films and on television.
She is the mother of Amy Irving, therefore making her the former mother- in- law of filmmakers Steven Spielberg and Bruno Barreto and the mother- in- law of documentary filmmaker Kenneth Bowser, Jr.
Baroness Gösta von dem Bussche-Haddenhausen
Baroness Gösta von dem Bussche- Haddenhausen( 26 January 1902 – 13 June 1996) was the mother of Prince Claus of the Netherlands, who was the Prince Consort of Queen Beatrix of the Netherlands, thus making her the mother- in- law of the former Dutch Queen.
She is also the paternal grandmother of King Willem- Alexander of the Netherlands, who is the current Dutch King.
Vera Miletić
Vera Miletić (Serbian Cyrillic: Вера Милетић; 8 March 1920 – 7 September 1944) was a Serbian student and soldier.
She was notable for being the mother of Mira Marković, posthumously making her the mother-in-law of Serbian president Slobodan Milošević.
Cornelia (mother of the Gracchi)
Cornelia( c. 190s – c. 115 BC) was the second daughter of Publius Cornelius Scipio Africanus, the hero of the Second Punic War, and Aemilia Paulla.
She is remembered as a prototypical example of a virtuous Roman woman.
She was the mother of the Gracchi brothers, and the mother- in- law of Scipio Aemilianus.
Ebba Eriksdotter Vasa
Ebba Eriksdotter Vasa (circa 1491 – 21 November 1549) was a Swedish noblewoman.
She was the mother of Queen Margaret Leijonhufvud and the second cousin and mother-in-law of King Gustav Vasa.
Thiadsvind
Thiadsvind also known as Theudesinda or Theodelinda (677 - ?) was the daughter of Redbad, King of the Frisians.
In 711 she was married to Grimoald the Younger the eldest son of Pepin of Herstal.
The marriage was officiated by archbishop or bishop of the Frisians Willibrord.
They had two sons: Theudoald and Arnold.

Question: Who is the mother-in-law of Thiadsvind?