Prime minister of Great Britain(*) (1783, 1807-09)
3rd Duke of Portland (1762-1809)
Born 1738 Died 1809
William Henry Cavendish-Bentinck, son of William, 2nd duke (1709-1762), and grandson of the 1st duke. His mother, Margaret, grand-daughter and heiress of John Holles, Duke of Newcastle, brought to her husband Welbeck Abbey and other estates in Nottinghamshire. He was born on the 14th of April 1738, and was educated at Oxford, where he graduated M.A. in 1757. In 1761, as Marquess of Titchfield, he became M.P. for the borough of Weobly (Hereford), but in May 1762 he was called to the upper house on the death of his father.
Under the Marquess of Rockingham he was, from July 1765 to December 1766, Lord Chamberlain, and on the return of Rockingham to power in April 1782 he was made Lord-Lieutenant of Ireland. After the short ministry of Shelburne, succeeding he death of Rockingham, the Duke of Portland was selected by Fox and North as a "convenient cipher" to become the head of the coalition ministry, to the formation of which the king was with great reluctance compelled to give his assent. The duke held the premiership from the 5th of April 1783 until the defeat of the bill for "the just and efficient government of British India" caused his dismissal from office on the 17th of December following. Under Pitt he was, from 1794 to 1801, secretary of state for the home department, after which he was, from 1801 to 1805, president of the council. In 1807 he was appointed a second time Prime Minister and First Lord of the Treasury. Ill health caused him to resign in October 1809, and he died on the 30th of that month. He owed his political influence chiefly to his rank, his mild disposition, and his personal integrity, for his talents were in no sense brilliant, and he was deficient in practical energy as well as in intellectual grasp.
He married in 1766 Lady Dorothy Cavendish (1750-1794), daughter of the 4th Duke of Devonshire, and was succeeded as 4th duke by his son William Henry (1768-1854), who married a daughter of the famous gambler, General John Scott, and was brother-in-law to Canning. His son, the 5th duke, William John Cavendish Bentinck-Scott (1800-1879) died unmarried. He is notable for having constructed the underground halls at Welbeck Abbey, and for his retiring habits of life, which gave occasion for some singular stories. He was succeeded by his cousin William John Arthur Charles James Cavendish-Bentinck (b. 1857) as 6th duke.
Being the entry for PORTLAND, WILLIAM HENRY CAVENDISH-BENTINCK, 3rd DUKE OF in the 1911 Encyclopedia Britannica, the text of which lies within the public domain.(* Note that the original text erroneously refers to William as the "Prime Minister of England".)