Romanos Argyros (10th century)
Romanos Argyros was a Byzantine aristocrat and son-in- law of Emperor Romanos I Lekapenos.
Charles Francis Norton
Charles Francis Norton( 1807 – 1835) was a 19th- century Member of Parliament for Guildford.
Norton was also a Captain of 52nd Light Infantry; son-in- law of Sir Colin Campbell; brother- in- law of writer Caroline Norton
Jenna Stern
Jenna Louise Stern (born September 23, 1967) is an American actress.
Having played 11 characters across the "Law & Order" franchise, she currently recurs on  as Judge Elana Barth, in addition to voicing commercials, books and documentaries.
Stern was born in Los Angeles, California.
Member of an artistic family, Stern is the daughter of actor and producer Tom Stern and Academy Award-nominated and Golden Globe-winning actress Samantha Eggar.
Her brother, Nicolas Stern, is a producer for film and television.
She married actor Brennan Brown in 1998.
Stern graduated from the U.C. Berkeley with a Bachelor of Arts and received her Master of Fine Arts from NYU Graduate Acting Program.
Robert Vadra
Robert Vadra is an Indian businessman, entrepreneur and the husband of Priyanka Gandhi.
He is the son -in- law of Sonia Gandhi and Rajiv Gandhi, and the brother- in- law of Rahul Gandhi.
Nicolas Stern
Nicolas Stern (born September 12, 1965) is an American film producer.
Member of an artist family, he is the son of Golden Globe-winning actress Samantha Eggar and actor/producer Tom Stern.
His sister, Jenna Stern, is a film actress.
Himansu Gupta
Himanshu Gupta is an Indian American Energy policy expert, engineer and social- entrepreneur in Climate Change.
He is the co-founder and CEO of ClimateAI and has worked for Al Gore as his India Advisory Fellow, at the Office of Nicholas Stern, Baron Stern of Brentford as a visiting associate and the Government of India( NITI Aayog, previously Planning Commission) as Energy and Climate change project lead.
In 2016, Himanshu was included in the prestigious Forbes 30 Under 30 list for his work in energy and climate change space in India.
Wyndham Goold
Wyndham Goold( 1812-1854) was a Member of Parliament( MP) for County Limerick from 1850 to 1854.
Goold was educated at Westminster School and Trinity College, Dublin.
He was the son in law of Frederick Falkiner Goold, Archdeacon of Raphoe and brother in law of Bishop Hamilton Verschoyle
Robert W. Levering
Robert Woodrow Levering( October 3, 1914 – August 11, 1989) was a U.S. Representative from Ohio, son-in- law of Usher L. Burdick and brother- in- law of Quentin N. Burdick.
Greg Penner
Gregory B. Penner( born December 18, 1969) is an American businessman and venture capitalist.
Penner was named the chairman of Walmart on June 5, 2015.
He is the son-in- law of S. Robson Walton and the grandson- in- law of Sam Walton, the founder of Walmart.
Nick Sidi
Nick Sidi( born 22 February 1966 in Manchester, England) is an English actor.
He is the son -in- law of actress Rosalind Knight and brother- in- law of actress Susannah Elliott- Knight.
He often plays drama or comedy roles on television and frequently appears in BBC dramas.

Question: Who is Nicolas Stern's sibling-in-law?
Answer: Brennan Brown