Daughter of Henry VIII by Rosemary Churchill

She was a daughter of Henry Cadogan, Viscount Chelsea, the son and heir of George Henry Cadogan, 5th Earl Cadogan. Alexandra Mary Cadogan (22 February 1900 – ), on 17 February 1920 in London. Marlborough married his first wife, The Hon. The grave of the 10th Duke of Marlborough and his first wife at St Martin's Church, Bladon. He was Mayor of Woodstock from 1937 to 1942.

Prior to inheriting the dukedom in 1934 he was a lieutenant-colonel in the Life Guards. Marlborough was born in London as the first of two sons born to Charles Spencer-Churchill, 9th Duke of Marlborough and his first wife, the former Consuelo Vanderbilt, an American railroad heiress. John Albert William Spencer-Churchill, 10th Duke of Marlborough DL (18 September 1897 – 11 March 1972), styled Marquess of Blandford until 1934, was a British peer. Hereinafter cited as The Complete Peerage. White, Duncan Warrand and Lord Howard de Walden, editors, The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct or Dormant, new ed., 13 volumes in 14 (1910-1959 reprint in 6 volumes, Gloucester, U.K.: Alan Sutton Publishing, 2000), volume VIII, page 504. He was Mayor of Woodstock from 1937 to 1942.'

John Albert Edward William Spencer-Churchill, 10th Duke of Marlborough, DL (18 September 1897 – 11 March 1972), styled Marquess of Blandford until 1934, was a British military officer and peer.

Daughter of Henry VIII by Rosemary Churchill