At the end of 2 Henry VI, York killed Clifford's father. Clifford's grief at the fact that York didn't spare his aged father led him to swear he would kill even the youngest child of the house of York, which he accomplishes by murdering Rutland.
Margaret holds her lords off when they want to kill York, apparently because she wants to taunt him before she kills him. With a handkerchief dipped in Rutland's blood, she challenges him to mourn for his son while she charges him with having an upstart's desire for the throne. He accuses Margaret of having the opposite characteristics of everything that embodies femininity, which makes her a monster. Taking up arms was virtually unheard of for a woman in this time, though Margaret probably had heard of Joan of Arc, who led the forces in France at the time of Margaret's betrothal to Henry. While soldiering was an uncharacteristically masculine activity for a woman, Margaret's actions are driven by a stereotypically feminine desire to care for her son and assure his rightful future. York accuses her of behaving unnaturally, yet she nevertheless demonstrates a kind of "natural" tendency to defend her offspring to the death.
After escaping through many battles and debates through the prior two plays, York's luck finally runs out. Despite the fact that the contemporary title of this play was Richard Duke of York, York dies in the first act of the play. Theoretically he has won the right to the throne, though the legality of his agreement with Henry is debatable; yet he is unable to become king, and Henry outlives him. The ambiguous prediction of the spirits summoned by the Duke of Gloucester's wife in 2 Henry VI finally comes true, as a duke overcomes a king, yet the king outlives this duke. Now the focus of the York line shifts to his remaining sons, and their struggles.