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.
Bill Dundee
William" Bill" Cruickshanks( born 24 October 1943) is a Scottish born- Australian professional wrestler and author better known by his stage name Bill Dundee.
Cruickshanks is the father of Jamie Dundee and the father- in- law of wrestler Bobby Eaton.
Ogawa Mataji
Viscount was a general in the early Imperial Japanese Army.
He was also the father- in- law of Field Marshal Gen Sugiyama.
Erskine Hamilton Childers
Erskine Hamilton Childers (11 December 1905 – 17 November 1974) was an Irish Fianna Fáil politician who served as the fourth President of Ireland from June 1973 to November 1974.
He is the only Irish president to have died in office.
He also served as Tánaiste and Minister for Health from 1969 to 1973, Minister for Transport and Power from 1959 to 1969, Minister for Posts and Telegraphs from 1951 to 1954 and 1966 to 1969, Minister without portfolio in July 1959, Minister for Lands from 1957 to 1959 and Parliamentary Secretary to the Minister for Local Government from 1944 to 1948.
He served as a Teachta Dála (TD) from 1938 to 1973.
His father Robert Erskine Childers, a leading Irish republican and author of the espionage thriller "The Riddle of the Sands", was executed during the Irish Civil War.
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.
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.
Mohammad Ilyas (cricketer)
Mohammad Ilyas Mahmood( born March 19, 1946, Lahore, Punjab) is a former Pakistani cricketer who played in ten Tests from 1964 to 1969.
He is the father- in- law of Imran Farhat.
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).
Rita Childers
Margaret "Rita" Childers (19 July 1915 – 9 May 2010) was a press attaché at the British Embassy in Dublin, who became the wife of the 4th President of Ireland, Erskine Hamilton Childers, and later was a possible candidate for the presidency.
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.

Question: Who is the father-in-law of Rita Childers?
Answer: Robert Erskine Childers