Lady Arbella Stuart was an English noblewoman who was considered a possible successor to Queen Elizabeth I of England. During the reign of King James VI and I, she married William Seymour, 2nd Duke of Somerset, another claimant to the English throne, in secret. King James imprisoned William Seymour and placed her under house arrest. When she and her husband tried to escape England, she was captured and imprisoned in the Tower of London, where she died at age 39.

William Seymour, 2nd Duke of Somerset, was an English nobleman and Royalist commander in the English Civil War.