Mary Boleyn (c. 1499/1500 – 19 July 1543) was the sister of English queen consort Anne Boleyn and a member of the Boleyn family, which enjoyed considerable influence during the reign of King Henry VIII of England. Some historians claim she was Anne’s younger sister, but her children believed Mary was the elder, as do most historians today.
Mary was one of the mistresses of Henry VIII, from a period of roughly 1521 to 1526. It has been rumoured that she bore two of the king’s children, though Henry did not acknowledge either of them as he had done with Henry FitzRoy, his son by Bessie Blount. Mary was also rumoured to have been a mistress of Henry VIII’s rival, King Francis I of France, for some period between 1515 and 1519. She was the maternal aunt of Queen Elizabeth I of England.
Mary Boleyn was married twice: in 1520 to William Carey, and secretly in 1534, the year after sister Anne married the king, to William Stafford, a soldier of good family but few prospects. This secret marriage to a man considered beneath her station angered both Henry VIII and her sister, Queen Anne, and resulted in Mary’s banishment from the royal court; she spent the remainder of her life in obscurity, dying seven years after sister Anne’s execution.
– Taken from Mary Boleyn’s Wikipedia Page.