Their main rendezvous was at Saint Augustine’s Abbey, outside the city. The abbot was an old enemy of Thomas’s, Ranulf had assured William, but nevertheless William decided to tell him that they had come to arrest Thomas, not to kill him. That was a pretense they would keep up until the last moment: no one was to know the true aim of the operation except for William himself, Ranulf, and the four knights who had crossed from France.

They reached the abbey at noon. The men Ranulf had summoned were waiting. The abbot gave them dinner. His wine was very good and they all drank plenty. Ranulf briefed the men-at-arms who would surround the cathedral close and prevent anyone from escaping.

William kept shivering, even when he stood beside the fire in the guesthouse. It should be a simple operation, but the penalty for failure would probably be death. The king would find a way to justify the murder of Thomas, but he could never support the attempted murder: he would have to deny all knowledge of it and hang the perpetrators. William had hanged many people, as sheriff of Shiring, but the thought of his own body dangling at the end of a rope still made him shake.

He turned his mind to the thought of the earldom he could expect as a reward for success. It would be nice to be an earl again in his old age, respected and deferred to and obeyed without question. Perhaps Aliena’s brother, Richard, would die in the Holy Land and King Henry would give William his old estates again. The thought warmed him more than the fire.

When they left the abbey they were a small army. Nevertheless they had no trouble getting into Canterbury. Ranulf had controlled this part of the country for six years and he had not yet relinquished his authority. He held more sway than Thomas, which was no doubt why Thomas had complained so bitterly to the pope. As soon as they were inside, the men-at-arms spread out around the cathedral close and blocked all the exits.

The operation had begun. Until this moment it had been theoretically possible to call the whole thing off, with no harm done; but now, William thought with a shiver of dread, the die was cast.

He left Ranulf in charge of the blockade, keeping a small group of knights and men for himself. He installed most of the knights in a house opposite the main gateway to the cathedral close. Then he went through the gate with the remainder. Reginald Fitzurse and the other three conspirators rode into the kitchen courtyard as if they were official visitors, rather than armed intruders. But William ran into the gatehouse and held the terrified porter at sword point.

The attack was under way.

With his heart in his mouth, William ordered a man-at-arms to tie up the porter, then summoned the rest of his men into the gatehouse and closed the gate. Now no one could enter or leave. He had taken armed control of a monastery.

He followed the four conspirators into the kitchen courtyard. There were stables to the north of the yard, but the four had tied their horses to a mulberry tree in the middle. They took off their sword belts and helmets: they would keep up the facade of a peaceful visit a little longer.

William caught up with them and dropped his weapons under the tree. Reginald looked inquiringly at him. “All’s well,” William said. “The place is isolated.”

They crossed the courtyard to the palace and went into the porch. William assigned a local knight called Richard to stay in the porch on guard. The others entered the great hall.

The palace servants were sitting down to dinner. That meant they had already served Thomas and the priests and monks who were with him. One of the servants stood up. Reginald said: “We are the king’s men.”

The room went quiet, but the servant who had stood up said: “Welcome, my lords. I’m the steward of the hall, William Fitzneal. Please come in. Would you like some dinner?”

He was remarkably friendly, William thought, considering that his master was at loggerheads with the king. He could probably be suborned.

“No dinner, thank you,” said Reginald.

“A cup of wine, after your journey?”

“We have a message for your master from the king,” Reginald said impatiently. “Please announce us right away.”

“Very good.” The steward bowed. They were unarmed, so he had no reason to refuse them. He left the table and walked to the far end of the hall.

William and the four knights followed. The eyes of the silent servants went with them. William was trembling the way he used to before a battle, and he wished the fighting would start, for he knew he would be all right then.

They all went up a staircase to the upper floor.

They emerged in a roomy attendance chamber with benches around the sides. There was a large throne in the middle of one wall. Several black-robed priests and monks were sitting on the benches, but the throne was empty.

The steward crossed the room to an open door. “Messengers from the king, my lord archbishop,” he said in a loud voice.

There was no audible reply, but the archbishop must have nodded, for the steward waved them in.

The monks and priests stared wide-eyed as the knights marched across the room and went into the inner chamber.

Thomas Becket was sitting on the edge of the bed, dressed in his archbishop’s robes. There was only one other person in the room: a monk, sitting at Thomas’s feet, listening. William caught the monk’s eye, and was jolted to recognize Prior Philip of Kingsbridge. What was he doing here? Currying favor, no doubt. Philip had been elected bishop of Kingsbridge, but had not yet been confirmed. Now, William thought with savage glee, he never would be.

Philip was equally startled to see William. However, Thomas carried on speaking, pretending not to notice the knights. This was a piece of calculated discourtesy, William thought. The knights sat down on the low stools and benches around the bed. William wished they had not: it made the visit seem social, and he felt they had lost impetus somehow. Perhaps that was what Thomas had intended.

Finally Thomas looked at them. He did not rise to greet them. He knew them all, except William, and his eye came to rest on Hugh Morville, the highest-ranking. “Ah, Hugh,” he said.

William had put Reginald in charge of this part of the operation, and so it was Reginald, not Hugh, who spoke to the archbishop. “We come from the king in Normandy. Do you want to hear his message in public or in private?”

Thomas looked irritably from Reginald to Hugh and back again, as if he resented dealing with a junior member of the delegation. He sighed, then said: “Leave me, Philip.”

Philip stood up and walked past the knights, looking worried.

“But don’t close the door,” Thomas called after him.

When Philip had gone out, Reginald said: “I require you in the name of the king to go to Winchester to answer charges against you.”

William had the satisfaction of seeing Thomas go pale. “So that’s how it is,” the archbishop said quietly. He looked up. The steward was hovering at the door. “Send everyone in,” Thomas said to him. “I want them all to hear this.”

The monks and priests filed in, Prior Philip among them. Some sat down and others stood around the walls. William had no objection: on the contrary, the more people who were present, the better; for the object of this unarmed encounter was to establish before witnesses that Thomas refused to comply with a royal command.

When they were all settled, Thomas looked at Reginald. “Again?” he said.

“I require you in the name of the king to go to Winchester to answer charges against you,” Reginald repeated.

“What charges?” Thomas said quietly.

“Treason!”

Thomas shook his head. “I will not be put on trial by Henry,” he said calmly. “I’ve committed no crime, God knows.”

“You’ve excommunicated royal servants.”