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.

[1] His younger brother was Lord Ivor Spencer-Churchill who joined the Royal Army Service Corps and fought in the First World War.

[6] His mother was the eldest child, and only daughter, of William Kissam Vanderbilt, a New York railroad millionaire, and the former Alva Erskine Smith.

[8] Prior to inheriting the dukedom in 1934, he was a lieutenant-colonel in the Life Guards, and served with distinction in France and Belgium during World War I.

[citation needed] He enlisted during World War II and was a military liaison officer with the United States forces in Britain.

[8] In 1950, the Duke opened the grounds and many rooms of Blenheim Palace (including the bedroom in which Sir Winston Churchill was born) to the public to help defray the cost of upkeep.

[9] Together, they had two sons and three daughters: Six weeks before his death, on 26 January 1972, the Duke married his second wife, (Frances) Laura (née Charteris) Canfield (1915–1990), the widow of the American publishing heir Michael Temple Canfield (whose first wife had been Caroline Lee Bouvier, the sister of First Lady Jacqueline Kennedy Onassis).

Through his eldest daughter, Lady Sarah (who inherited the bulk of his mother's estate upon her death in 1965),[25] he was a grandfather of four: Serena Mary Churchill Russell (b.

[citation needed] Through his youngest son, Lord Charles, he was a grandfather of three: Rupert John Harold Mark Spencer-Churchill (b.