Dukes of Portland

Dukedom of Portland
Heraldic achievement displaying arms of Bentinck (Azure, a cross moline argent) quartering Cavendish (Sable, three stag's heads cabossed argent attired or a crescent for difference)
Creation date	6 July 1716
Monarch	George I
Peerage	Peerage of Great Britain
First holder	Henry Bentinck, 1st Duke of Portland
Last holder	Victor Cavendish-Bentinck, 9th Duke
Remainder to	the 1st Duke's heirs male of the body lawfully begotten
Subsidiary titles	Marquess of Titchfield; Earl of Portland; Viscount Woodstock; Baron Cirencester Baron Bolsover (1880 – 1977)
Extinction date	30 July 1990
Former seat(s)	Welbeck Abbey

Earl of Portland is a title that has been created twice in the Peerage of England, first in 1633 and again in 1689. The title Duke of Portland was created in 1716 but became extinct in 1990 upon the death of the ninth Duke, when the Earldom was inherited by a distant cousin.

The title of Earl of Portland was first created for the politician Richard Weston, 1st Baron Weston, in 1633. He was Chancellor of the Exchequer from 1621 to 1628 and Lord High Treasurer from 1628 to 1635, and had already been created Baron Weston, of Neyland in the County of Suffolk, in 1628. This title was also in the Peerage of England. He was succeeded by his son, the second Earl. He served as Joint Lord Lieutenant of Hampshire. His son, the third Earl, was killed at the Battle of Lowestoft in 1665. He was unmarried and was succeeded by his uncle, the fourth Earl. He was childless and on his death in 1688 the titles became extinct.

The title was created for a second time in 1689 in favour of William Bentinck, the Dutch favourite and close advisor of King William III. He was made Baron Cirencester and Viscount Woodstock at the same time he was given the earldom, also in the Peerage of England. He was succeeded in 1709 by his son from his first marriage, Henry, the second Earl of Portland. He represented Southampton and Hampshire in the House of Commons. In 1716 he was created Marquess of Titchfield and Duke of Portland in the Peerage of Great Britain. His grandson, William Cavendish-Bentinck, 3rd Duke of Portland was a noted politician. He was Prime Minister in 1783 and from 1807 to 1809 and also served as Home Secretary and as Lord President of the Council. In 1801 he assumed by Royal licence the additional surname of Cavendish. Portland was the husband of Lady Dorothy Cavendish, daughter of William Cavendish, 4th Duke of Devonshire, and was a descendant on his mother's side of Henry Cavendish, 2nd Duke of Newcastle-upon-Tyne.