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 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.