Dorothy Macmillan

Lady Dorothy Evelyn Macmillan (née Cavendish) was born on 28 July 1900 and died on 21 May 1966. She was an English socialite and the third daughter of Victor Cavendish, 9th Duke of Devonshire, and Evelyn Cavendish, Duchess of Devonshire. Her early childhood was spent primarily at Holker Hall in Lancashire, where she lived for her first eight years, and at Lismore Castle in Ireland. In 1908, her father succeeded to the dukedom, and the family relocated to Chatsworth House in Derbyshire, along with other ducal estates.

Lady Dorothy received education in French, German, riding, and golf during her upbringing. At the age of sixteen, she moved to Rideau Hall in Ottawa, where her father was serving as the Governor General of Canada, and resided there until around 1916.

In 1920, she married Harold Macmillan, a publisher and Conservative politician who had previously worked on her father's staff in Canada. Their wedding took place on 21 April at St Margaret's Church in Westminster. It was attended by members of royalty, aristocracy, and leading literary figures, and was regarded as a significant social event of the London season.

As the wife of Harold Macmillan, who later became Prime Minister of the United Kingdom from 1957 to 1963, Lady Dorothy assumed the role of a political spouse. Her marriage lasted until her death and was characterized by her dutiful support of her husband's political career. Despite this, she maintained a long-term affair with Conservative politician Robert Boothby, beginning in 1929. This affair was kept secret from the wider public but was known within high society circles.

Lady Dorothy and Harold Macmillan had four children:

- Maurice Macmillan (1921–1984), who was a Conservative politician and publisher. He married The Hon Katharine Ormsby-Gore, daughter of the 4th Baron Harlech. Maurice outlived his mother by nearly three years.

- Lady Caroline Macmillan (1923–2016), who married Julian Faber and had five children.

- Lady Catherine Macmillan (1926–1991), who married Julian Amery, later Baron Amery of Lustleigh, a Conservative politician; they had four children.

- Sarah Macmillan (1930–1970), who married Andrew Heath in 1953 and had two children.

In 1951, Lady Dorothy underwent an abortion, which resulted in her inability to have further biological children. Subsequently, the family adopted two sons. Her personal life was marked by difficulties, including a drinking problem, and she died of a heart attack at the Macmillan family estate at Birch Grove in West Sussex in 1966. Her husband, Harold Macmillan, who was created Earl of Stockton in 1984, survived her by 20 years.

Lady Dorothy's personal affairs, notably her long-standing relationship with Robert Boothby, have been documented, revealing her complex personal life and its impact on her marriage and family.