James Armour (Master mason)
James Armour (15 January 1730 – 20 September 1798) was a master mason and father of Jean Armour, and therefore the father-in-law of the poet Robert Burns.
Ludwig von Westphalen
Johann Ludwig von Westphalen( 11 July 1770 – 3 March 1842) was a liberal Prussian civil servant and the father- in- law of Karl Marx.
Peter Burroughs
Peter Burroughs( born 27 January 1947) is a British television and film actor, the director of Willow Management.
He is the father- in- law of actor and TV presenter Warwick Davis.
John Adams (merchant)
John Adams( 1672 or 1673 – 1745) was an American- born Canadian merchant and member of the Nova Scotia Council.
He was the father- in- law of Henry Newton( politician).
Countess Xenia Czernichev-Besobrasov
Countess Xenia Czernichev-Besobrasov (Chernysheva-Besobrasova ; 11 June 1929
Paris20 September 1968, Casteau, Belgium) was the first wife of Archduke Rudolf of Austria, the youngest son of the last reigning Emperor of Austria-Hungary, Charles I.
John Vernou Bouvier III
John Vernou" Black Jack" Bouvier III( May 19, 1891 – August 3, 1957) was an American Wall Street stockbroker and socialite.
He was the father of First Lady Jacqueline Kennedy Onassis and of socialite Lee Radziwill, and was the father- in- law of John F. Kennedy.
Barthold A. Butenschøn Sr.
Hans Barthold Andresen Butenschøn( 27 December 1877 – 28 November 1971) was a Norwegian businessperson.
He was born in Kristiania as a son of Nils August Andresen Butenschøn and Hanna Butenschøn, and grandson of Nicolay Andresen.
Together with Mabel Anette Plahte( 1877 – 1973, a daughter of Frithjof M. Plahte) he had the son Hans Barthold Andresen Butenschøn Jr. and was through him the father- in- law of Ragnhild Butenschøn and grandfather of Peter Butenschøn.
Through his daughter Marie Claudine he was the father- in- law of Joakim Lehmkuhl, through his daughter Mabel Anette he was the father- in- law of Harald Astrup( a son of Sigurd Astrup) and through his daughter Nini Augusta he was the father- in- law of Ernst Torp.
He took commerce school and agricultural school.
He was hired in the family company N. A. Andresen& Co, and became a co-owner in 1910.
He eventually became chief executive officer.
The bank changed its name to Andresens Bank in 1913 and merged with Bergens Kreditbank in 1920.
The merger was dissolved later in the 1920s.
He was also a landowner, owning Nedre Skøyen farm and a lot of land in Enebakk.
He chaired the board of Nydalens Compagnie from 1926, having not been a board member before that.
He also chaired the supervisory council of Forsikringsselskapet Viking and Nedre Glommen salgsforening, and was a supervisory council member of Filharmonisk Selskap.
He was a member of the gentlemen's club SK Fram since 1890, and was proclaimed a lifetime member in 1964.
He was buried in Enebakk.
Archduke Rudolf of Austria (1919–2010)
Archduke Rudolf of Austria (5 September 1919 – 15 May 2010) was the sixth child and youngest son of Emperor Charles I of Austria and Zita of Bourbon-Parma.
Archduke Simeon of Austria
Archduke Simeon of Austria( Simeon Carl Eugen Joseph Leopold; born 29 June 1958 in Katana, South Kivu, Belgian Congo) is a member of the House of Habsburg- Lorraine.
He is the third- eldest child of Archduke Rudolf of Austria and his first wife, Countess Xenia Czernichev- Besobrasov.
Simeon is a paternal grandson of Charles I of Austria and Zita of Bourbon- Parma.
Ogawa Mataji
Viscount was a general in the early Imperial Japanese Army.
He was also the father- in- law of Field Marshal Gen Sugiyama.

Question: Who is the father-in-law of Countess Xenia Czernichev-Besobrasov?
Answer: Charles I of Austria