Lady Dorothy Macmillan

Lady Dorothy Evelyn Macmillan (' Cavendish'''; 28 July 1900 – 21 May 1966) was an English socialite and the third daughter of Victor Cavendish, 9th Duke of Devonshire, and Evelyn Cavendish, Duchess of Devonshire.

She was married to Harold Macmillan from 1920 until her death.

In 1920 she married publisher and Conservative politician Harold Macmillan, who had been on her father's staff in Canada.

Their lavish wedding, on 21 April at St Margaret's, Westminster, was attended by royalty, aristocracy and leading literary figures, and was hailed as the social event of the London season.

In 1929 Lady Dorothy began a lifelong affair with the Conservative politician Robert Boothby, an arrangement that scandalised high society but remained unknown to the general public.

Philip Frere, a partner in Frere Cholmely solicitors, urged Macmillan not to divorce his wife, which at that time would have been fatal to a public career even for the "innocent party".

Macmillan and Lady Dorothy lived largely separate lives in private thereafter.

He was often treated with condescension by his aristocratic in-laws and was observed to be a sad and isolated figure at Chatsworth in the 1930s.

Campbell suggests that Macmillan's humiliation was first a major cause of his odd and rebellious behaviour in the 1930s then, in subsequent decades, made him a harder and more ruthless politician than his rivals Eden and Butler.

The stress caused by this may have contributed to Macmillan's nervous breakdown in 1931.

Lady Dorothy was a dutiful political wife and the couple remained together (despite her long-lasting affair with Conservative politician Robert Boothby) until her death from a heart attack at the Macmillan family estate at Birch Grove, West Sussex, in 1966.

She spent her first eight years at Holker Hall, Lancashire (located in the county of Cumbria post-1974); and Lismore Castle, Ireland.

She became known as Lady Dorothy from the age of eight, when her father succeeded to the dukedom of Devonshire, and the family moved into Chatsworth House, Derbyshire, and the other ducal estates.

She received lessons in French, German, riding and golf.

From the age of sixteen she lived with the family at Rideau Hall, Ottawa, where her father served as Governor General of Canada.

Her husband, who was created Earl of Stockton in 1984, outlived her by 20 years.

She and Harold had four children: