The elder sister of David Bowes-Lyon married a prince who was the last Emperor of what country?
David Bowes-Lyon Sir David Bowes-Lyon KCVO (2 May 1902 – 13 September 1961) was the sixth son of Claude Bowes-Lyon, 14th Earl of Strathmore and Kinghorne, and Cecilia Nina Cavendish-Bentinck as well as their tenth and youngest child. His elder sister Lady Elizabeth Bowes-Lyon married Prince Albert, Duke of York, the second son of King George V, in 1923 and became Queen Consort of the United Kingdom after the abdication of her husband's elder brother Edward VIII on 11 December 1936.
Princess Catherine Ivanovna of Russia Princess Catherine Ivanovna of Russia (Russian: Княжна Екатери́на Иоа́нновна ; 12 July 1915 – 14 July 2007) was a great-great-granddaughter of Tsar Nicholas I of Russia and a niece of King Alexander I of Yugoslavia. She was the last member of the Imperial Family to be born before the fall of the dynasty, and was ultimately to become the last surviving uncontested dynast of the Imperial House of Russia.