William Cavendish

William Cavendish MP was born on 10 January 1783 and died on 14 January 1812. He was an English nobleman associated with the Whig political party. His father was Lord George Cavendish, who later became the Earl of Burlington.

Cavendish received his education at Eton College. Between 1800 and 1803, he studied at Trinity College, Cambridge. In 1803–1804, he undertook a continental Grand Tour, a traditional educational journey among European countries, during which he visited Berlin to observe the reviews of the Prussian Army.

During his lifetime, Cavendish was involved in military service at home; he was commissioned as a Captain in the Derbyshire Militia in 1803. He was promoted to Major in 1804 and served as the Colonel of the Derbyshire Militia from 1811 until his death in 1812.

His political career included being elected as the Member of Parliament for Knaresborough in May 1804, and shortly thereafter, in July 1804, he was elected MP for Aylesbury. In the general election of 1806, he was elected to represent Derby and remained its MP until his death in 1812.

Cavendish married Louisa O'Callaghan on 18 July 1807. She was the daughter of Cornelius O'Callaghan, 1st Baron Lismore. Their marriage produced four children, with the youngest born after Cavendish's death. Their children were:

- William Cavendish, who later became the 7th Duke of Devonshire (1808–1891)

- Lady Fanny Cavendish (11 April 1809 – 30 December 1885), who married Frederick John Howard

- Lord George Henry Cavendish (19 August 1810 – 23 September 1880)

- Lord Richard Cavendish (3 July 1812 – 19 November 1873)

Upon William Cavendish’s death in 1812 at the age of 29, his younger children, including Lord George and Lord Richard, gained precedence of the children of a duke through a Royal Warrant issued in 1858, following his brother's later succession.

William Cavendish was killed in an accident in Holker Park on the evening of 14 January 1812. He was returning from a shooting excursion with his brother Charles and a college tutor known as Rev. Mr. Smith. The carriage reins broke while driving, and as Cavendish attempted to regain control, he was thrown from the curricle and died instantly. His brother Charles was unharmed, but Rev. Mr. Smith suffered a broken rib.

Following his death, Cavendish's father was elevated to the peerage as Earl of Burlington in 1831. The title was inherited by William's son, who succeeded as the 7th Duke of Devonshire.