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 Herzeleide of Prussia Princess Herzeleide-Ina-Marie Sophie Charlotte Else of Prussia (25 December 1918 – 22 March 1989) was a member of the deposed House of Hohenzollern. She was the only daughter of Prince Oskar of Prussia (the second youngest son of Emperor Wilhelm II) and his morganatic wife ,Countess Ina Marie von Bassewitz. She is the mother of Ernst-Johann Biron, Prince of Courland, the current head of the House of Biron.