Caris recovered her composure. “Try to keep him comfortable, and come and fetch me immediately there’s any change.”

“Thank you, sister,” said Madge. “I don’t know what we’ll do without you.”

Merthin was thoughtful on the journey back to Kingsbridge. Even Lolla’s bright, meaningless chatter did not bring him out of his mood. Ralph had learned a lot, but he had not changed deep down. He was still a cruel man. He neglected his child-wife, barely tolerated his parents and was vengeful to the point of mania. He enjoyed being a lord, but felt little obligation to care for the peasants in his power. He saw everything around him, people included, as being there for his gratification.

However, Merthin felt optimistic about Kingsbridge. All the signs were that Mark would become alderman on All Hallows’ Day, and that could be the start of a boom.

Merthin got back on the last day of October, All Hallows’ Eve. It was a Friday this year, so there was not the influx of crowds that came when the night of evil spirits fell on a Saturday, as it had in the year that Merthin was eleven, and he met the ten-year-old Caris. All the same the people were nervous, and everyone planned to be in bed by nightfall.

On the main street he saw Mark Webber’s eldest son, John. “My father is in the hospital,” the boy said. “He has a fever.”

“This is a bad time for him to fall sick,” Merthin said.

“It’s an ill-starred day.”

“I didn’t mean because of the date. He has to be present at the parish guild meeting tomorrow. An alderman can’t be elected in his absence.”

“I don’t think he’ll be going to any meetings tomorrow.”

That was worrying. Merthin took his horses to the Bell and left Lolla in the care of Betty.

Entering the priory grounds, he ran into Godwyn with his mother. He guessed they had dined together and now Godwyn was walking her to the gate. They were deep in an anxious conversation, and Merthin guessed they were worried about the prospect of their placeman Elfric losing the post of alderman. They stopped abruptly when they saw him. Petranilla said unctuously: “I’m sorry to hear that Mark is unwell.”

Forcing himself to be civil, Merthin replied: “It’s just a fever.”

“We will pray that he gets well quickly.”

“Thank you.”

Merthin entered the hospital. He found Madge distraught. “He’s been coughing blood,” she said. “And I can’t quench his thirst.” She held a cup of ale to Mark’s lips.

Mark had a rash of purple blotches on his face and arms. He was perspiring, and his nose was bleeding.

Merthin said: “Not so good today, Mark?”

Mark did not seem to see him, but he croaked: “I’m very thirsty.” Madge gave him the cup again. She said: “No matter how much he drinks, he’s always thirsty.” She spoke with a note of panic that Merthin had never heard in her voice before.

Merthin was filled with dread. Mark made frequent trips to Melcombe, where he talked to sailors from plague-ridden Bordeaux.

Tomorrow’s meeting of the parish guild was the least of Mark’s worries now. And the least of Merthin’s, too.

Merthin’s first impulse was to cry out to everyone the news that they were in mortal danger. But he clamped his mouth shut. No one listened to a man in a panic, and besides he was not yet sure. There was a small chance Mark’s illness was not what he feared. When he was certain, he would get Caris alone and speak to her calmly and logically. But it would have to be soon.

Caris was bathing Mark’s face with a sweet-smelling fluid. She wore a stony expression that Merthin recognized: she was hiding her feelings. She obviously had some idea of how serious Mark’s illness was.

Mark was clutching something that looked like a scrap of parchment. Merthin guessed it would have a prayer written on it, or a verse of the Bible, or perhaps a magic spell. That would be Madge’s idea – Caris had no faith in writing as a remedy.

Prior Godwyn came into the hospital, trailed as usual by Philemon. “Stand away from the bed!” Philemon said immediately. “How will the man get well if he cannot see the altar?”

Merthin and the two women stood back, and Godwyn bent over the patient. He touched Mark’s forehead and neck, then felt his pulse. “Show me the urine,” he said.

The monk-physicians set great store by examination of the patient’s urine. The hospital had special glass bottles, called urinals, for the purpose. Caris handed one to Godwyn. It did not take an expert to see that there was blood in Mark’s urine.

Godwyn handed it back. “This man is suffering from overheated blood,” he said. “He must be bled, then fed sour apples and tripes.”

Merthin knew, from his experience of the plague in Florence, that Godwyn was talking rubbish, but he made no comment. In his mind there was no longer much room for doubt about what was wrong with Mark. The skin rash, the bleeding, the thirst: this was the illness he himself had suffered in Florence, the one that had killed Silvia and all her family. This was la moria grande.

The plague had come to Kingsbridge.

As darkness fell on All Hallows’ Eve, Mark Webber’s breathing became more difficult. Caris watched him weaken. She felt the angry impotence that possessed her when she was unable to help a patient. Mark passed into a state of troubled unconsciousness, sweating and gasping although his eyes were closed and he showed no awareness. At Merthin’s quiet suggestion, Caris felt in Mark’s armpits, and found large boil-like swellings there. She did not ask him the significance of this: she would question him later. The nuns prayed and sang hymns while Madge and her four children stood around, helplessly distraught.

At the end Mark convulsed, and blood jetted from his mouth in a sudden flood. Then he fell back, lay still and stopped breathing.

Dora wailed loudly. The three sons looked bewildered, and struggled to hold back unmanly tears. Madge wept bitterly. “He was the best man in the world,” she said to Caris. “Why did God have to take him?”

Caris had to fight back her own grief. Her loss was nothing compared with theirs. She did not know why God so often took the best people and left the wicked alive to do more wrong. The whole idea of a benevolent deity watching over everyone seemed unbelievable at moments such as this. The priests said sickness was a punishment for sin. Mark and Madge loved one another, cared for their children and worked hard: why should they be punished?

There were no answers to religious questions, but Caris had some urgent practical inquiries to make. She was deeply worried by Mark’s illness, and she could guess that Merthin knew something about it. She swallowed her tears.

First she sent Madge and her children home to rest, and told the nuns to prepare the body for burial. Then she said to Merthin: “I want to talk to you.”

“And I to you,” he said.

She noticed that he looked frightened. That was rare. Her fear deepened. “Come to the church,” she said. “We can talk privately there.”

A wintry wind swept across the cathedral green. It was a clear night, and they could see by starlight. In the chancel, monks were preparing for the All Hallows dawn service. Caris and Merthin stood in the northwest corner of the nave away from the monks, so that they could not be overheard. Caris shivered, and pulled her robe closer around her. She said: “Do you know what killed Mark?”

Merthin took a shaky breath. “It’s the plague,” he said. “La moria grande.”

She nodded. This was what she had feared. But all the same she challenged him. “How do you know?”

“Mark goes to Melcombe and talks to sailors from Bordeaux, where the bodies are piled in the streets.”