Thou hast undone thyself, thy son, and me,
And giv’n unto the house of York such head
As thou shalt reign but by their sufferance!
To entail him and his heirs unto the crown,
What is it but to make thy sepulcher
And creep into it far before thy time?
(1.1.233–38)

With these words, Margaret berates Henry for his decision to entail the Crown to York. For one thing, this deal inadvisable from a political perspective, since she believes that York will surely attempt to assassinate him. More importantly, Henry’s decision makes him an unnatural father, since he has disinherited his son, Prince Edward. Margaret’s evident concern for her son marks a shift in her character from Henry VI, Part 2. Whereas in that play she schemed for her own advancement, in Part 3 her actions seem primarily motivated by maternal love. It is for her son’s sake that she takes command of the king’s army. And when she ultimately loses the war, her arc comes to and end not with her death, but with that of her son, whose murder she is forced to watch.

Look, York, I stained this napkin with the blood
That valiant Clifford with his rapier’s point
Made issue from the bosom of the boy.
And if thine eyes can water for his death,
I give thee this to dry thy cheeks withal.
Alas, poor York, but that I hate thee deadly
I should lament thy miserable state.
I prithee grieve to make me merry, York.
(1.4.80–87)

Margaret says these words as she hands York a “napkin” soaked in the blood of his son, the earl of Rutland. The audience witnessed the scene of Rutland’s murder, which took place at the hands of the vengeful Clifford. Now Margaret is capitalizing on Clifford’s act for the sake of her own revenge. In what is perhaps her most shocking moment of cruelty in the entire Henry VI sequence, Margaret tauntingly invites York to dry his tears with a kerchief already saturated with blood. This act will give York cause to condemn Margaret as an unnatural mother: “How couldst thou drain the lifeblood of the child / To bid the father wipe his eyes withal, /And yet be seen to bear a woman’s face?” (1.4.139–41). Considering that Margaret is ostensibly motivated by the protection of her own son, the bitter irony of York’s condemnation hits hard.

And what is Edward but a ruthless sea?
What Clarence but a quicksand of deceit?
And Richard but a raggèd fatal rock?
        . . . That’s a threefold death.
This speak I, lords, to let you understand,
If case some one of you would fly from us,
That there’s no hoped-for mercy with the brothers York
More than with ruthless waves, with sands, and rocks.
Why, courage then—what cannot be avoided
’Twere childish weakness to lament or fear.
(5.4.25–27, 31–38)

Margaret addresses these words to her troops as she prepares to lead them into the final battle with Edward’s forces. She draws out an earlier metaphor in which she likened her army to a damaged ship that must nonetheless keep sailing its course. Here, she notes that the York brothers each present additional dangers to their “ship”—Edward is a “ruthless sea,” Clarence [i.e., George] is “a quicksand of deceit,” and Richard is “a raggèd fatal rock.” Her point is that the danger of “threefold death” represented by these men means that her troops have no option but to fight. If they were to flee or surrender, the brothers York would kill them as ruthlessly as “waves,” “sands,” and “rocks.” Margaret’s message is as powerful as the rhetoric she uses to express it, demonstrating her skill as a military leader.