Act IV is a very long act. In 4.1 four women go to the Tower: Elizabeth (widow of Edward IV), the Duchess of York (mother of Richard and Clarence), the Duchess of Gloucester (Lady Anne, Richard’s wife, formerly the wife of the son of Henry VI), along with a woman we have not yet met, Clarence’s daughter. This is the first time we have seen Lady Anne since the big wooing scene in 1.2. Why have we not seen or heard of her since then? Now she regrets her marriage, blames her “woman’s heart” for yielding to Richard, and curses herself. Given all these women on stage, it’s odd that there is as yet no mention of Elizabeth’s daughter, whom Richard will soon seek to wed. Why not? Maybe we have enough trouble keeping four women separate in our minds. We also meet Dorset (a son to Queen Elizabeth), who will be important later, when he joins Richmond.
In 4.2 Buckingham arranges to have the princes killed, but doesn’t do it himself. This is the first sign that there is a limit to his villainy, and of his incipient parting from Richard. We again hear of the old prophecy that Richmond will be king. Richard doesn’t care to hear it. He then refuses to honor his promise to Buckingham, the next step in Buckingham’s departure. For a cunning politician, Richard seems oddly clueless here. It’s unclear whether Buckingham withdraws primarily because he was appalled at the murder of the princes or because Richard refused to honor his promise. Both?
In 4.3 Tyrrel, the assassin, in soliloquy indicates that he and the two men he hired had some conscience, were not hardened killers after all. (This separates them from Richard, who is the only one in the play without a conscience.) Maybe that’s why he doesn’t simply enter and inform Richard that the deed was done. Richard then previews his plan to get rid of his wife and become a “wooer” again and marry Elizabeth’s daughter. Is that so we will be prepared for his astounding proposal (to Elizabeth) in the next scene?
4.4 is the biggest scene in the play, 538 lines. It opens with a soliloquy from old Queen Margaret, announcing that she has been lurking in order to get her revenge, in some sense ‘answering’ Richard’s soliloquy back in 1.1. The other major women come on stage — Elizabeth the Yorkist queen and the Duchess of York. Elizabeth has lost her husband and two sons, as well as her brother and brother-in-law. The Duchess of York has lost two sons. Margaret, who hangs back and mutters dark cursing asides, exulting in the pain of the Queen and Duchess, has lost her husband and her son. But when she sits down with the other women I expected that she might sympathize with them, but no, she continues to “scorn” them. All the women agree, however, in cursing Richard, “a hellhound that doth hunt all to death.” It’s quite shocking to hear a mother formally curse her own son. But this is only the beginning to the scene’s shocks. Richard enters, prepared for war against Buckingham, and Richard now tells Elizabeth that he wants to marry her daughter, who happens also to be his niece, presumably because the marriage with Lady Anne did not work out — she hates him. It raises again the question of why Richard wanted to marry Lady Anne: maybe it was just to prove that he could. Marriages in these history plays are usually designed for political purposes, i.e., to cement an alliance. But Richard wants to marry the daughter of Elizabeth only to prevent her from marrying Richmond (which would strengthen his claim to the throne).
In a very long seduction speech, Richard explains that he killed the brothers of his intended for love of her, recalling his claim to Lady Anne in 1.2 that he killed her husband for love of her. This is even more shocking than a mother cursing her son. The scene goes on and on, falling into rapid-fire exchange of one-liners (but not stichomythia), and Elizabeth — here’s the third shock — yields! I think this would present a challenge to an actress: how you get from continuing bitterness at line 396 to agreement at line 428? (She realizes that she is being “tempted by the devil,” and she yields, as did Lady Anne back in 1.1. Do we perhaps agree with Richard, who says, after she leaves, that she is a “Relenting fool, and shallow, changing woman”?)
In the remainder of the scene Richard is rattled by news of Richmond and Buckingham, and speaks abusingly to his friends, especially Stanley. Again, he seems much less in control of his impulses than he did at the beginning of the play.) A series of messengers bring good news and bad, and then in the brief 4.5 we get the expected scene of Stanley preparing to leave Richard.
Act 4 seems to the center on the women of the play, first the four women at the Tower, all of whom have grievances against Richard of course. Queen Elizabeth’s parting address to the stones of the Tower, which are about to immure her two “babies,” becomes a prophetic curse of Richard. Buckingham’s withdrawal from Richard’s side seems to hinge on Richard’s treatment of him, but it is murky; Richard certainly denies him favor, and Buckingham responds by leaving him. 4.3 confirms Tyrrell’s killing the princes, with the detail of the pity of the actual murderers, which contrasts with the unfeeling reception of the news by Richard. Richard speaks of Anne’s death, but it’s unclear in the play when this happens. (In historical fact she did die before Richard, so his proxy wooing of his niece, Elizabeth, has some possibility, even if not
historical.) And as you note, this sets up that proxy wooing of the next scene.
And that scene does seem a center of the play, encompassing as it does the old queen Margaret as well as the duchess of York and Queen Elizabeth. It’s a striking reprise of his earlier wooing of Anne and positions Richard against the force of these royal women. His “relenting fool, and shallow, changing woman” may seem apt in the circumstance, but feeble in the combined force of what the group of them represent. The messengers that arrive forecast something of what’s coming.