She drew him behind a pillar and kissed him on the mouth, the tip of her tongue running lightly across his lips.

They kissed every chance they got: in church, in the market place, when they met on the street, and – best of all – when he was at her house and they found themselves alone. He lived for those moments. He thought about kissing her before he went to sleep and again as soon as he woke up.

He visited her house two or three times a week. Her father, Edmund, liked him, though her aunt Petranilla did not. A convivial man, Edmund often invited Merthin to stay for supper, and Merthin accepted gratefully, knowing it would be a better meal than he would get at Elfric’s house. He and Caris would play chess or draughts, or just sit talking. He liked to watch her while she told a story or explained something, her hands drawing pictures in the air, her face expressing amusement or astonishment, acting every part in a pageant. But, most of the time, he was waiting for those moments when he could steal a kiss.

He glanced around the church: no one was looking their way. He slipped his hand inside her coat, and touched her through the soft linen of her dress. Her body was warm. He held her breast in his palm, small and round. He loved the way her flesh yielded to the press of his fingertips. He had never seen her naked, but he knew her breasts intimately.

In his dreams they went farther. Then, they were alone somewhere, a clearing in the woods or the big bedchamber of a castle; and they were both naked. But, strangely, his dreams always ended a moment too soon, just before he entered her; and he would wake up frustrated.

One day, he would think; one day.

They had not yet spoken about marriage. Apprentices could not marry, so he had to wait. Caris must, surely, have asked herself what they were going to do when he finished his term; but she had not voiced those thoughts. She seemed content to take life one day at a time. And he had a superstitious fear of talking about their future together. It was said that pilgrims should not spend too much time planning their journey, for they might learn of so many hazards that they would decide not to go.

A nun walked past, and Merthin withdrew his hand guiltily from Caris’s bosom; but the nun did not notice them. People did all sorts of things in the vast space of the cathedral. Last year Merthin had seen a couple having sexual congress up against the wall of the south aisle, in the darkness of the Christmas Eve service – although they had been thrown out for it. He wondered if he and Caris could stay here throughout the service, dallying discreetly.

But she had other ideas. “Let’s go to the front,” she said. She took his hand and led him through the crowd. He knew many of the people there, though not all: Kingsbridge was one of the larger cities in England, with about seven thousand inhabitants, and no one knew everybody. He followed Caris to the crossing, where the nave met the transepts. There they came up against a wooden barrier blocking entrance to the eastern end, or chancel, which was reserved for clergy.

Merthin found himself standing next to Buonaventura Caroli, the most important of the Italian merchants, a heavy-set man in a richly embroidered coat of thick wool cloth. He came originally from Florence – which he said was the greatest city in the Christian world, more than ten times the size of Kingsbridge – but he now lived in London, managing the large business his family had with English wool producers. The Carolis were so rich they loaned money to kings, but Buonaventura was amiable and unpretentious – though people said that in business he could be implacably hard.

Caris greeted the man in a casually familiar way: he was staying at her house. He gave Merthin a friendly nod, even though he must have guessed, from Merthin’s age and hand-me-down clothing, that he was a mere apprentice.

Buonaventura was looking at the architecture. “I have been coming to Kingsbridge for five years,” he said, making idle conversation, “but until today I have never noticed that the windows of the transepts are much bigger than those in the rest of the church.” He spoke French with an admixture of words from the dialect of the Italian region of Tuscany.

Merthin had no trouble understanding. He had grown up, like most sons of English knights, speaking Norman French to his parents and English to his playmates; and he could guess the meanings of many Italian words because he had learned Latin in the monks’ school. “I can tell you why the windows are like that,” he said.

Buonaventura raised his eyebrows, surprised that an apprentice should claim such knowledge.

“The church was built two hundred years ago, when these narrow lancet windows in the nave and chancel were a revolutionary new design,” Merthin went on. “Then, a hundred years later, the bishop wanted a taller tower, and he rebuilt the transepts at the same time, putting in the bigger windows that had by then come into fashion.”

Buonaventura was impressed. “And how do you happen to know this?”

“In the monastery library there is a history of the priory, called Timothy’s Book, that tells all about the building of the cathedral. Most of it was written in the time of the great Prior Philip, but later writers have added to it. I read it as a boy at the monks’ school.”

Buonaventura looked hard at Merthin for a moment, as if memorizing his face, then he said casually: “It’s a fine building.”

“Are the buildings very different in Italy?” Merthin was fascinated by talk of foreign countries, their life in general and their architecture in particular.

Buonaventura looked thoughtful. “I believe the principles of building are the same everywhere. But in England I have never seen domes.”

“What’s a dome?”

“A round roof, like half a ball.”

Merthin was astonished. “I never heard of such a thing! How is it built?”

Buonaventura laughed. “Young man, I am a wool merchant. I can tell whether a fleece comes from a Cotswold sheep or a Lincoln sheep, just by rubbing the wool between my finger and thumb, but I don’t know how a henhouse is built, let alone a dome.”

Merthin’s master, Elfric, arrived. He was a prosperous man, and he wore expensive clothes, but they always looked as if they belonged to someone else. An habitual sycophant, he ignored Caris and Merthin, but made a deep bow to Buonaventura and said: “Honoured to have you in our city once again, sir.”

Merthin turned away.

“How many languages do you think there are?” Caris said to him.

She was always saying crazy things. “Five,” Merthin replied without thinking.

“No, be serious,” she said. “There’s English, and French, and Latin, that’s three. Then the Florentines and the Venetians speak differently, though they have words in common.”

“You’re right,” he said, entering into the game. “That’s five already. Then there’s Flemish.” Few people could make out the tongue of the traders who came to Kingsbridge from the weaving towns of Flanders: Ypres, Bruges, Ghent.

“And Danish.”

“The Arabs have their own language and, when they write, they don’t even use the same letters as we do.”

“And Mother Cecilia told me that all the barbarians have their own tongues that no one even knows how to write down – Scots, Welsh, Irish, and probably others. That makes eleven, and there might be people we haven’t even heard of!”

Merthin grinned. Caris was the only person he could do this with. Among their friends of the same age, no one understood the thrill of imagining strange people and different ways of life. She would ask a random question: What is it like to live at the edge of the world? Are the priests wrong about God? How do you know you’re not dreaming, right now? And they would be off on a speculative voyage, competing to come up with the most outlandish notions.