On 04 Feb 1520 William Carey (age 20) and Mary Boleyn (age 21) were married. Around the time, possibly shortly after, Mary Boleyn (age 21) became mistress to King Henry VIII of England and Ireland (age 28) leading to speculation one or both of her children were fathered by Henry (age 28). She the daughter of Thomas Boleyn 1st Earl Wiltshire and Ormonde (age 43) and Elizabeth Howard Countess of Wiltshire and Ormonde (age 40). He a great x 4 grandson of King Edward III of England.

The evidence for Mary being Henry's mistress:

Letters and Papers Foreign and Domestic. 20 Oct 1537. George Throckmorton letter relating to events around 1531 where Henry responds to an accusation that he had relationships with both Anne Boleyn's mother and sister "Never with the mother". Cromwell goes on the say never with the sister either.

Defense of the Unity of the Church Book III, 1536, letter from Cardinal Reginald Pole to King Henry VIII accusing him of double standards by attempting to annul his marriage with Queen Katherine on the basis of her having previously been married, albeit unconsummated, to Henry's brother Arthur, as a means to allow Henry to marry Anne Boleyn, with who sister Henry had had a carnal relationship.

1536 Letter from Ambassador Chapuys to the Emperor in which Chapuys writes "Others tell me that the said Archbishop had pronounced the marriage of the King and Concubine [Anne] invalid on account of the King having had connection with her sister [Mary].