John Albert Edward William Spencer-Churchill, 10th Duke of Marlborough, (18 September 1897 – 11 March 1972), styled Marquess of Blandford until 1934, was a British military officer and peer. Early life He was born in London on 18 September 1897 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. His younger brother was Lord Ivor Spencer-Churchill who joined the Royal Army Service Corps and fought in the First World War. His parents separated in 1906 and divorced in 1921. Later that year his mother married Lt. Col. Jacques Balsan, a French balloon, aircraft, and hydroplane pilot, and his father married the French American Gladys Deacon. His paternal grandparents were George Spencer-Churchill, 8th Duke of Marlborough and his first wife, Lady Albertha Hamilton (a daughter of James Hamilton, 1st Duke of Abercorn and Lady Louisa Russell). His mother was the eldest child, and only daughter, of William Kissam Vanderbilt, a New York railroad millionaire, and the former Alva Erskine Smith. They divorced in 1895; she married his friend Oliver Belmont and he married the widow Anna Harriman. His maternal uncles were William Kissam Vanderbilt II and Harold Stirling Vanderbilt. Marlborough was educated at Eton before joining the Life Guards. Career 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. After the war, he served as Mayor of Woodstock, where Blenheim is located, from 1937 to 1942. His wife served as the first woman mayor of Woodstock. He also served as High Steward of Oxford in 1937. He enlisted during World War II and was a military liaison officer with the United States forces in Britain. 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. Today, he is known as one of the originators of the "stately homes" business. Personal life On 17 February 1920, he was married to the Hon. Alexandra Mary Cadogan (1900–1961) at a ceremony at St Margaret's Church in London attended by King George V and Queen Mary. As a wedding gift, his maternal grandfather gave him a house in London. She was a daughter of Henry Cadogan, Viscount