Charles Seymour, 6th Duke of Somerset the pride of birth and rank amounted almost to a disease". Charles was the second son of Charles Seymour, 2nd Baron Seymour of Trowbridge (died 1665), of Marlborough Castle in Wiltshire, by his wife Elizabeth Alington (1635–1692). The 2nd baron was (in a junior line) a great-great-grandson of Edward Seymour, 1st Duke of Somerset (executed 1552), brother of Queen Jane Seymour, uncle of King Edward VI and Lord Protector of England. Charles was educated at Harrow School and Trinity College, Cambridge, where his portrait by Nathaniel Dance-Holland survives in the College's collection. In 1675, Charles's elder brother Francis Seymour, 5th
Charles Seymour, 6th Duke of Somerset 1748 and was buried in the Seymour Chapel of Salisbury Cathedral in Wiltshire, where survives the elaborate monument to his ancestor Edward Seymour, 1st Earl of Hertford (1539–1621), son of the 1st Duke of Somerset. Shortly before his death he foresaw that his own line of the Seymour family was about to die out in the male line and that as was said of the 9th Duke of Norfolk (d.1777) "the honours of his family were about to pass away from his own line to settle on that of a distant relative". His son and heir apparent Algernon Seymour, Earl