William Seymour, 2nd Duke of Somerset was the great-grandson of Edward Seymour, 1st Duke of Somerset (c.1500-1552), the uncle of King Edward VI and Lord Protector of England. Seymour made a secret marriage at Greenwich on 22 June 1610 to Arbella Stuart (d.1615), daughter of Charles Stuart, 1st Earl of Lennox and Elizabeth Cavendish. Arbella was thirteen years his senior, and King James I disapproved of the marriage as the union of two potential Tudor pretenders to the throne, who were respectively fourth and sixth in line, could only be seen as a threat to the ruling dynasty. As a result, William was condemned to life
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,