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
Edward Seymour, 16th Duke of Somerset Depot, with the temporary rank of lieutenant-colonel (ordnance officer, 2nd class) from 4 January 1900. He eventually became Inspector of Army Ordnance Services, and retired from the army in 1918. Seymour established his claim to the dukedom in 1925, the 15th Duke of Somerset having died without issue in 1923. He was the great-great-grandson of the Very Reverend Lord Francis Seymour, fourth and youngest son of the 8th Duke. On 28 July 1881, Seymour married Rowena Wall, a daughter of George Wall, of Colombo, Ceylon. Together, they had one son: Evelyn Seymour, 17th Duke of Somerset, born on 1 May