Lord Charles Bentinck

Bentinck was the third son of British Prime Minister William Cavendish-Bentinck, 3rd Duke of Portland and Lady Dorothy (1750–1794), daughter of Prime Minister William Cavendish, 4th Duke of Devonshire. William Bentinck, 4th Duke of Portland, and Lord William Bentinck were his elder brothers.

Bentinck was returned to Parliament for Ashburton in 1806, a seat he held until 1812. He served under the Earl of Liverpool as Treasurer of the Household between 1812 and 1826.

Bentinck married, firstly, Georgiana Augusta Frederica Seymour (baptized Elliott) (1782-10 December 1813), daughter of the courtesan Mrs Grace Elliott on 21 September 1808; she was said to be a daughter of the Prince of Wales or of the 4th Earl of Cholmondeley, both men claiming her paternity. They had one daughter, who was raised after Georgiana's death by Lord Cholmondeley, according to the entry on Grace Elliott. The marriage enabled Bentinck to become Treasurer of the Household in 1812, a position he held till death, despite his involvement in a notorious divorce suit and his subsequent remarriage.

In 1815 he eloped with his mistress, Lady Abdy, daughter of Richard Wellesley, 1st Marquess Wellesley, and Hyacinthe Gabrielle Roland, and wife of Bentinck's friend Sir William Abdy, 7th Baronet. Lady Anne was divorced by her husband, and she and Bentinck were married on 16 July 1816. They had four children:

• Anne Cavendish-Bentinck (d. 7 June 1888)
• Emily Cavendish-Bentinck (d. 6 June 1850), married Henry Hopwood.
• Reverend Charles William Frederick Cavendish-Bentinck (1817–1865). He was a great-grandfather of Queen Elizabeth II.
• Lieutenant-General Arthur Cavendish-Bentinck (10 May 1819 – 11 December 1877). He married first Elizabeth Sophia Hawkins-Whitshed. They were parents of William Cavendish-Bentinck, 6th Duke of Portland. He married secondly Augusta Browne, 1st Baroness Bolsover, and they had three sons and a daughter, Lady Ottoline Morrell.

Anne and Lord Charles became lovers at some point during her first marriage. They eloped on 5 September 1815, following which Abdy brought a suit for criminal conversation (crim.con. in Regency parlance) for 30,000 pounds but won only 7,000 pounds in damages. (These damages were never paid by the impecunious Bentinck). During the discussion of the divorce bill, the customary provision against remarriage was struck out in the House of Lords. Lady Abdy (or rather, her husband Sir William Abdy) was granted a divorce on 25 June 1816. Anne and Lord William were married on 23 July 1816, enabling their first child (which she was expecting) to be born legitimate three weeks later.

Bentinck died on 28 April 1826 at age 45. His wife survived him by almost 50 years and died in March 1875.