Claudio walked me across to a rattling elevator, which took us down to what he called the bunker. This was the Manuscript Depository, built in the seventies to cope with the great inward flood of material that the Archives had had to cope with in the postwar period. It was an underground library, a basic, unadorned, ugly place, with shelving spread over two stories, and mesh flooring and steel stairs connecting everything. Some of the shelves were locked, holding sensitive material, and others were empty, waiting for more material yet to come.

We went through into the Parchment Room, where some of the more famous documents were stored for display. They were held in chests of drawers, each waist-high, with ten glass-topped drawers in each. These pieces could be stunning — often in Latin, some illuminated, others covered by wax seals.

Claudio kept up an engaging and practiced patter. From its very earliest days, even in the days of persecution, the church in Rome had adopted the imperial habit of record keeping. The first archives had been called the scrinium sanctum, a bit of language that startled me with recognition. But the archives were far from complete. The first collections had been burned around A.D. 300 by the Emperor Diocletian. When Christianity had become the religion of the Empire, the accretion of records had begun again. Little had survived, however, from the bloody turbulence of the first millennium.

In the fourteenth century the popes had, for a time, been exiled to France, and in the fifteenth a period of infighting had peaked with three rival popes rampaging around Europe — “A bibliographer’s nightmare,”

said Claudio laconically. The later popes had started trying to unify the archives in the sixteenth century. But when Napolй on had taken Italy, he hauled the whole lot away to France for a few years, doing still more damage in the process …

“But all we have is here,” Claudio said. “There are letters from popes as far back as Leo the First, from the fifth century, who faced down Attila the Hun. We have diplomas from Byzantine emperors. The correspondence of Joan of Arc. Reports of papal enclaves, accusations of witchcraft and other skulduggery in high places, sexual secrets of kings, queens, bishops, and a few popes. The records of the Spanish Inquisition, details of the trial of Galileo … Even the letter from England asking for the dissolution of the first marriage of Henry the Eighth.”

“And somewhere in all this,” I said, “is the true story of the Order. Or at least as the Vatican saw it.”

He waved a hand. “What I’m trying to tell you is that the archives are overwhelming. There are scholars who have spent most of their lives in here. It isn’t even all cataloged, and our only search engine is shoe leather. The idea that someone like your friend can just come in here—”

“Peter said you would be like this,” I said bluntly.

He looked aristocratically bemused. “I’m sorry? Like what?”

“Obstructive. It’s true, isn’t it? It’s just as when you stalled over giving me a contact with the Order in the first place. You don’t want to come right out and refuse to help. Instead you’re trying to put me off.”

He pursed his lips, his eyes cloudy. I felt a stab of guilt; perhaps he hadn’t even been aware of what he was doing. “Perhaps I’m not sure if I should help you.”

Something in the way he said that triggered an idea in my head. I said at random, “But you could help us, if you wanted to. Because you’ve done searches here on the Order yourself. ”

He wouldn’t concede that, but his aristocratic nostrils flared. “You are making big inductive leaps.”

“If you have, you could help Peter find what he wants very quickly.”

“You haven’t told me why I should.”

“Because of Lucia.” I knew Peter had told him about the girl. “Here’s the bottom line. Peter and I think she is coming to harm, because of the Order. I certainly don’t know for sure that she isn’t. You’re a priest; you wear the collar. Can you really turn away from a child in trouble? … You can’t, can you?” I said slowly, thinking as I spoke. “And that’s why you’ve done your own researches. You’ve had your own suspicions about the Order—”

He said nothing. He was right that I was making big inductive leaps in the dark, but sometimes my nose is good. Still, I could see he was in conflict, pulled by two opposing loyalties.

“Look,” I said, “help us. I give you my word that we will do you no harm.”

“ I don’t matter,” he said, with a priest’s steely moral authority.

“Very well — no harm to anything you hold dear. My word, Claudio. And perhaps we will do a lot of good.”

He said little more that day. He showed me out, his remaining conversation brief and stiff. I suspected I had compromised whatever friendship I had with him.

But a day later, perhaps after sleeping on it, he got in touch.

Under Claudio’s guidance, Peter immersed himself in the archives for days on end. And he surfaced with a string of tales: the diaries of pilgrims and nobles, records of wars and sackings, the account of a thwarted love affair — and even a mention of one of my own ancestors, a different George Poole …

George Poole had first come to Rome in 1863, in the company of the British government’s chief commissioner of works, Lord John Manners. Poole was a surveyor. It had been a time when the Modern Age, in the form of hydraulics, telegraphs, steam power, and railways, was just beginning to touch the old city, and British engineers, the best in the world, were at the forefront.

Poole had even been in the presence of the pope himself, for a time. He had seen the papal train, with its white-and-gold-painted coaches, and even a chapel on bogie wheels. The pope had come to the opening of a steel drawbridge, built by the British, across the Tiber at Porta Portese. The pontiff took a great interest in the new developments, and had asked to meet Manners and have the bridge mechanism explained to him — much to his lordship’s embarrassment, for in the middle of his working day he was carrying an umbrella and wearing an old straw hat.

When Poole came back to Rome twelve years later, it was in his own capacity as a consulting engineer. He returned at the invitation of a rather shadowy business concern fronted by one Luigi Frangipani, a member of what was said to be one of Rome’s great ancient families.

Poole expected that much would have changed. During his first visit it had been just three years since the great triumph of the Risorgimento had seen Italy unified under Victor Emanuele II. Now Rome was the capital of the new Italy. Among Poole’s circle of old friends, there had been great excitement at these developments, and much envy over his visit, for he was coming to a Rome free of the dominance of the popes for the first time in fourteen centuries.

But Poole was disappointed with what he found.

Even now the great political and technological changes seemed to have left no mark on Rome itself. Within its ancient walls, the city was still like a vast walled farm. He was startled to see cattle and goats being driven through the city streets, and pigs snuffling for acorns near the Flaminian Gate. The source of wealth was still agriculture and visitors, pilgrims and tourists; there was still no industry, no stock exchange.

But there were changes. He saw a regiment of bersaglieri, trotting through the streets in their elaborate operetta-extras’ uniforms. The clerics were much less in evidence, though you would see the cardinals’ coaches, painted black as if in mourning. He even glimpsed the king, a spectacularly ugly man, passing in his own carriage. He gathered that the king was a far more popular figure than the pope had ever been, if only for his family; after all, no pope since the Middle Ages had been in a position to display a grandson!