Paul Siogvolk
Paul Siogvolk (real name Albert Mathews) (September 8, 1820 – September 9, 1903) was an American author, lawyer and editor.
He was also the step-father of Alice Claypoole Vanderbilt.
László Széchenyi
Count László Széchenyi de Sárvár- felsővidék( 18 February 1879 – 5 July 1938) was an Austro Hungarian military officer, Imperial Chamberlain, diplomat and venture capitalist.
His great- uncle was István Széchenyi.
László Széchenyi married Gladys Vanderbilt, the youngest daughter of Alice Claypoole Gwynne and Cornelius Vanderbilt II.
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.
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.
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.
Cornelius Vanderbilt II
Cornelius Vanderbilt II (November 11, 1843 – September 12, 1899) was an American socialite, businessman, and a member of the prominent United States Vanderbilt family.
He was the favorite grandson of Commodore Cornelius Vanderbilt, who bequeathed him $5 million, and the eldest son of William Henry "Billy" Vanderbilt (who bequeathed him about $70 million) and Maria Louisa Kissam.
In his turn he succeeded them as head of the New York Central and related railroad lines in 1885.
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.
Alice Claypoole Vanderbilt
Alice Claypoole Gwynne Vanderbilt (November 11, 1845 – April 24, 1934) was the wife of Cornelius Vanderbilt II and reigned as the matriarch of the Vanderbilt family for over 60 years.
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.

Question: Who is Alice Claypoole Vanderbilt's mother-in-law?
Answer: Maria Louisa Kissam