Then Brother Thomas spoke up. “Has anyone in Kingsbridge ever been involved in a project that involved building below water level?”

Merthin knew the answer was No. He felt a surge of hope. This could rescue it for him.

Thomas went on: “I would like to know how both men would handle that problem.”

Merthin was ready with his solution – but he was afraid that if he spoke first Elfric would simply echo him. He compressed his lips, hoping that Thomas – who usually helped him – would get the message.

Thomas caught Merthin’s eye, and said: “Elfric, what would you do?”

“The answer is simpler than you think,” Elfric said. “You just have to drop loose rubble into the river at the point where your pier will stand. The rubble rests on the river bottom. You put more and more in until the pile is visible above water level. Then you build your pier on that foundation.”

As Merthin had expected, Elfric had come up with the crudest solution to the problem. Now Merthin said: “There are two snags with Elfric’s method. One is that a pile of rubble is no more stable under water than on land. Over time, it will shift and drop, and when that happens the bridge will subside. If you want a bridge to last only a few years, fine. But I think we should build for the long term.”

He heard a quiet rumble of concurrence.

“The second problem is the shape of the pile. It will naturally slope outwards below the water line, restricting the passage of boats, especially when the river is low. And Elfric’s arches are already narrow.”

Elfric said irritably: “What would you do instead?”

Merthin suppressed a smile. That was what he had wanted to hear – Elfric admitting that he did not know a better answer. “I’ll tell you,” he said. And I’ll show everyone that I know better than the idiot who chopped my door to pieces, he thought. He looked around. They were all listening. Their decision hung on what he would say next.

He took a deep breath. “First, I would take a pointed wooden stake and piledrive it into the river bed. Then I would bang in another next to it, touching; then another. In that way I would build a ring of stakes around the place in the river where I want to put my pier.”

“A ring of stakes?” Elfric jeered. “That will never keep the water out.”

Brother Thomas, who had asked the question, said: “Listen to him, please. He listened to you.”

Merthin said: “Next, I would build a second ring inside the first, with a gap between them of half a foot.” He sensed that he had his audience’s attention now.

“It still won’t be waterproof,” said Elfric.

Edmund said: “Shut up, Elfric, this is interesting.”

Merthin went on: “Then I would pour a clay mortar into the gap between the two rings. The mixture would displace the water, being heavier. And it would plug any chinks between the wood stakes, making the ring watertight. This is called a coffer dam.”

The room was quiet.

“Finally, I would remove the water from inside by bucket, exposing the river bed, and build a mortared stone foundation.”

Elfric was dumbstruck. Both Edmund and Godwyn were staring at Merthin.

Thomas said: “Thank you both. Speaking for myself, that makes the decision an easy one.”

“Yes,” said Edmund. “I rather think it does.”

Caris was surprised that Godwyn had wanted Elfric to design the bridge. She understood that Elfric would seem a safer choice – but Godwyn was a reformer, not a conservative, and she had expected him to be enthusiastic about Merthin’s clever, radical design. Instead he had timidly favoured the cautious option.

Fortunately, Edmund had been able to outmanoeuvre Godwyn, and now Kingsbridge would have a well-built, beautiful bridge that would allow two carts to cross at the same time. But Godwyn’s eagerness to appoint the unimaginative sycophant rather than the bold man of talent was an ominous sign for the future.

And Godwyn had never been a good loser. When he was a boy Petranilla had taught him to play chess, letting him win to encourage him, and he had challenged his uncle Edmund; but after being beaten twice he had sulked and refused to play again. He was in the same mood after the meeting in the guild hall, she could tell. It was probably not that he was particularly attracted to Elfric’s design. But he undoubtedly resented having the decision taken out of his hands. Next day, when she and her father went to the prior’s house, she anticipated trouble.

Godwyn greeted them coolly and did not offer any refreshment. As always, Edmund pretended not to notice slights. “I want Merthin to start work on the bridge immediately,” he said as he sat down at the table in the hall. “I have pledges of money for the full amount of Merthin’s budget-”

“From whom?” Godwyn interrupted.

“The town’s wealthiest traders.”

Godwyn continued to look inquiringly at Edmund.

Edmund shrugged and said: “Fifty pounds from Betty Baxter, eighty from Dick Brewer, seventy from myself, and ten pounds each from eleven others.”

“I didn’t know our citizens possessed such riches,” Godwyn said. He seemed both awestruck and envious. “God has been kind.”

Edmund added: “Kind enough to reward people for a lifetime’s hard work and worry.”

“No doubt.”

“Which is why I need to give them reassurances about the return of their money. When the bridge is built, the tolls will come to the parish guild, which will use them to repay loans – but who will collect the pennies as the passengers cross the bridge? I think it has to be a servant of the guild.”

“I never agreed to this,” Godwyn said.

“I know, that’s why I’m raising it now.”

“I mean, I never agreed to pay the tolls to the parish guild.”

“What?”

Caris stared at Godwyn, flabbergasted. Of course he had agreed to it – what was he talking about? He had spoken to her as well as to Edmund and assured them that Brother Thomas-

“Oh,” she said. “You promised that Thomas would build the bridge, if he was elected prior. Then, when Thomas withdrew and you became the candidate, we assumed…”

“You assumed,” Godwyn said. A smirk of triumph played about his lips.

Edmund could barely contain himself. “This is not square dealing, Godwyn!” he said in a choked voice. “You knew what the understanding was!”

“I knew no such thing, and you should call me Father Prior.”

Edmund’s voice got louder. “Then we’re back where we were with Prior Anthony three months ago! Except that now, instead of an inadequate bridge, we have no bridge at all. Don’t imagine it will be built at no cost to you. Citizens may lend their life savings to the priory, on the security of income from the bridge tolls, but they will not give their money away… Father Prior.”

“Then they must manage without a bridge. I have only just become prior – how can I start by alienating a right that has belonged to my priory for hundreds of years?”

“But it’s only temporary!” Edmund exploded. “And if you don’t do this no one will gain any money from bridge tolls because there will be no cursed bridge!”

Caris was furious, but she bit her tongue and tried to figure out what Godwyn was up to. He was getting his revenge for last night, but did he really mean it? “What do you want?” she said to him.

Edmund looked surprised by the question, but he said nothing: the reason he brought Caris with him to meetings was that she often saw things he missed, and asked questions he had not thought of.

“I don’t know what you mean,” Godwyn replied.

“You’ve pulled a surprise,” she said. “You’ve caught us wrong-footed. Very well. We admit we made an assumption that may have been unwarranted. But what’s your purpose? Just to make us feel stupid?”

“You asked for this meeting, not I.”

Edmund burst out: “What kind of way is that to talk to your uncle and your cousin?”