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
Lord Edward Seymour (died 1593) Welsh, etc.) of Cathanger, Fivehead, Somerset, Justice of the Common Pleas in 1563, MP for Cricklade (1547), Bristol (twice in 1553, twice in 1554, 1555, 1559, 1563), Somerset (1558) by whom he had one son: After the male line of the Seymour Dukes of Somerset in descent from the 1st Duke and his second wife Anne Stanhope failed on the death of Algernon Seymour, 7th Duke of Somerset (1684–1750), of Petworth House in Sussex (5th cousin of the 5th Baronet), the Berry Pomeroy family inherited the Dukedom in accordance with the special remainder, in the person of Sir Edward Seymour,