Charles Seymour, 6th Duke of Somerset (13 August, 1662 - December 2, 1748), succeeded his brother Francis , the 5th Duke, when the latter was shot in 1678 at the age of twenty, by a Genoese gentleman, named Horatio Botti, whose wife Somerset was said to have insulted at Lerici. Charles, who thus inherited the Barony of Seymour of Trowbridge along with the Dukedom of Somerset, was educated at Trinity College, Cambridge; and in 1682 he married a great heiress, Elizabeth, daughter of Joceline Percy, Earl of Northumberland, who brought him immense estates, including Alnwick Castle, Petworth, Syon House and Northumberland House in London. In 1683 Somerset received an appointment in the king’s household, and two years later a colonelcy of dragoons; but at the revolution he bore arms for the Prince of Orange. Having befriended Princess Anne in 1692, he became a great favourite with her after her accession to the throne, receiving the post of Master of the Horse in 1702. Finding himself neglected by Marlborough, he made friends with the Tories, and succeeded in retaining the queen’s confidence, while his wife replaced the Duchess of Marlborough as Mistress of the Robes in 1711. In the memorable crisis when Anne was at the point of death, Somerset acted with Argyll, Shrewsbury and other Whig nobles who, by insisting on their right to be present in the Privy Council, secured the Hanoverian succession to the Crown. He retained the office of Master of the Horse under George I till 1716, when he was dismissed and retired into private life; he died at Petworth on 2 December 1748. The duke’s first wife having died in 1722, he married secondly, in 1726, Charlotte, daughter of the 2nd Earl of Nottingham. He was a remarkably handsome man, and inordinately fond of taking a conspicuous part in court ceremonial; his vanity, which earned him the sobriquet of "the proud duke," was a byword among his contemporaries and was the subject of numerous anecdotes; Macaulay’s description of him as "a man in whom the pride of birth and rank amounted almost to a disease," is well known.

|- style="text-align: center;" | width="30%" |Preceded by:
The Earl of Grantham | width="40%" style="text-align: center;" |Master of the Horse
1702–1715 | width="30%" |Succeeded by:
In Commission