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.
Grand Duchess Xenia Alexandrovna of Russia Grand Duchess Xenia Alexandrovna of Russia (Russian: Ксения Александровна Романова ; 6 April [O.S. 25 March] 1875 – 20 April 1960) was the elder daughter and fourth child of Emperor Alexander III of Russia and Empress Maria Feodorovna of Russia (née Princess Dagmar of Denmark) and the sister of Emperor Nicholas II. She married a cousin, Grand Duke Alexander Mikhailovich of Russia, with whom she had seven children. She was the mother-in-law of Felix Yusupov and a cousin of Grand Duke Dmitri Pavlovich of Russia who, together, killed Grigori Rasputin, holy healer to her nephew, the haemophiliac Tsarevich Alexei Nikolaevich of Russia. During her brother's reign she recorded in her diary and letters increasing concern about his rule. After the fall of the monarchy in February 1917 she fled Russia, eventually settling in the United Kingdom.