Even at Bosworth, though they were to be found on the winning side at the very end, they had promised their loyalty and their army to Richard. At the start of the day they were sworn to be his allies. Richard even had Thomas Stanley’s son as a hostage, to prove their goodwill. He was certain they would ride to his aid even as they waited on the hill to see which way the battle was going, and then thundered down to support Henry.

And now, they have done it again. “Sans changer!” I choke. “Sans changer!”

It is the Stanley motto: never changing. But they are only unchanging in the pursuit of their own safety and success, and then I feel Maggie at my side and her fingers pinching the inside of my arm as she whispers urgently, “Stop it! Stop it!” and I bite the back of my hand and choke into silence.

But as my laughter drains away, I realize how powerful “the boy” has become. If the Stanleys have divided—one to Henry’s side, one to the boy’s—then they must know that he will invade and they must think that he might win. To have a Stanley on your side is like a pedigree—it shows that your claim is a good one. They only ever join a winning side. If Sir William is backing the boy it is only because he thinks he will triumph. If Lord Thomas has allowed it, it is because he thinks the boy has a good chance and a better claim.

Henry glances at me as I struggle to compose myself. He turns back to Sir William and his face is blank. “I gave you everything you asked for,” he says flatly, as though loyalty should be bought.

Sir William inclines his head.

“You yourself handed the crown of England to me on the battlefield.”

It is terrible how the people have fallen away from Sir William as if they have suddenly seen on him the pockmarks of the plague. Without seeming to move, everyone has receded from him by a clear pace and he stands alone, facing the king’s horrified gaze.

“You are my stepfather’s brother, I have treated you as an uncle.” Henry looks at his mother. She is swallowing convulsively as if bile is rising in her throat and she is going to vomit. “My mother assured me that you were her kinsman, you were a man we could trust.”

“A mistake,” Thomas, Lord Stanley, says. “Sir William can explain, I know . . .”

“There are forty important men promised with him,” Sir Robert prompts unasked. “He has recruited supporters. Between them they have sent the boy a fortune.”

“You are of the royal family of England and yet you side with a pretender?” Henry struggles with the words as if he cannot believe that he is saying this to his uncle. He had thought to shame me with the proof of my mother’s disloyalty, he had thought to shock the court with half a dozen names that he would send to the hangman to teach the others to be loyal in future. He did not think that in this theater of asserting his power he would find a traitor in his own family. I look at his mother, who is clinging to the back of his chair as her knees give way beneath her, looking with staring eyes from her husband to his brother as if they are equally faithless. At that horror-stricken glance from her I realize that they probably are. The brothers never act without each other. Perhaps they decided that Sir William would back the pretender and Thomas, Lord Stanley, maintain his fatherhood of the king. Both of them waiting to see who would win. Both of them determined to be on the winning side. Both of them judging that Henry Tudor was likely to lose.