The elder sister of David Bowes-Lyon married a prince who was the last Emperor of what country?
George VI George VI (Albert Frederick Arthur George; 14 December 1895 – 6 February 1952) was King of the United Kingdom and the Dominions of the British Commonwealth from 11 December 1936 until his death. He was the last Emperor of India and the first Head of the Commonwealth.
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.