Mary Boleyn, the sister of Anne Boleyn, has had an unfortunate reputation over the past half millennium. During her lifetime, rumors flew about her licentious behavior. She was alleged to be very free with her sexual favors, something that only high-born men, including kings, were allowed.
As a young teenager, Mary spent time at the French court of Francois I. It was suspected and has been repeated by historians throughout the last five hundred years, that she was Francois' mistress. We have a term for that today. It's called statutory rape. If a 13, 14, 15 year old girl did have sexual intercourse with the all-powerful king, it is very unlikely that she had much choice in the matter. But, as Weir points out in this study of Mary's life, there is really no independent proof that this ever happened.
Neither is there any real proof that, later, Mary became the mistress of Henry XIII or that she bore him at least one child. Henry never acknowledged the child, as he did many of his bastards, although he does seem to have made some provisions for her along the way, which may be an indirect evidence of the relationship.
Mary Boleyn was one of three children of a cold and calculating father, Thomas Boleyn. Thomas felt no compunction about using his children to further his ambitions. And he was very ambitious. Of the three children, Anne became queen, George flew very high at Henry's court, but Mary was always in the background. She never earned the fame - or notoriety - of the other two. That turned out to be a very fortunate thing for her.
In fact, in Weir's telling, Mary seems to have been a very ordinary woman with very ordinary dreams and desires. She married once in an arranged match and had two children in that marriage, a daughter and a son. The daughter may have actually been Henry's. The son pretty certainly was not. It was apparently not a particularly satisfying marriage, but then it ended with he death of her husband.
In good time, she met William Stafford, a soldier in the king's army, and Stafford, who was several years younger than Mary, fell in love with her. She did not immediately return his feelings, but after she got to know him, she did. They married secretly without asking permission of the king or queen, who by this time was Mary's sister, Anne. For a high-born woman to marry in such a manner was a great scandal. But it seems to have been worth it to Mary because she was very happy in her marriage.
Weir has meticulously researched this story and the footnotes and appendicies are extensive. In the end, we know all about the speculation concerning Mary Boleyn's life, but we also know that, for the most part, it is just speculation made up of the fevered imaginations of male historians over the centuries. In truth, very little is actually known for certain about this woman's life. She will ever remain a mystery.