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
Duke of Somerset from England and his estates were seized. At the Restoration his estates were restored, and he claimed the dukedom of Somerset as promised to him by Charles I. However this claim was rejected by the House of Lords and so was the title of Earl of Glamorgan. This enabled King Charles II to grant the Ducal title to the fourth creation family, the Seymours, who descend from the country's effective Regent, the Lord Protector in 1547. Edward Seymour (1538–1621) was son and heir of Edward Seymour, 1st Duke of Somerset, from his second marriage. He was created the Earl of