“Once it became the religion of the Empire, the church quickly tightened up. Heresy wasn’t to be tolerated: for the first time you had Christians cheerfully persecuting other Christians. In the centuries that followed, as the popes got a grip, the church became centralized, legalized, politicized, militarized. The Order would have had no place in the worldview of the popes.”

“Yet it survived.”

He rubbed his chin. “The Order is obviously secretive, but it’s been sitting there an awfully long time, an hour’s walk from the Vatican itself. The church has to know about it. There have to be some kind of links.” He smiled. “I told you I always wanted to go have a root around in the Vatican’s Secret Archives. Maybe now’s the time.”

I said dubiously, “I’ll have to ask Claudio.”

I wasn’t happy with his response. On some level he might be right. But he hadn’t taken on board what I’d tried to tell him about what I thought of as the earthy aspects of the Crypt: the faces, the smells, that deep pull I felt to remain there, to go back. Or maybe I hadn’t wanted to expose all this spooky biological stuff to him.

Anyhow, though I couldn’t shape the thought, I was sure there was more to the Order than just a cult. But maybe Peter was going to have to see it for himself.

As if on cue, an opportunity to do just that offered itself.

Peter had booted up his laptop—he was never without it—and every so often he checked his email. Now he discovered a note from some American kid called Daniel Stannard, who had somehow found his way through the Internet jungle to us. Daniel had concerns about a girl called Lucia, who sounded like she was some kind of refugee from the Order. Daniel wanted to meet us.

Peter smiled, a bit glassily. “I think the door of our secretive subterranean sisterhood has opened, just a crack.”

Right then I was drunk enough not to care. “I wonder if my great-grannie really did shag King Arthur.”

He snorted. “She’d have had a job, as he never existed . . .”

There were traces of history about Arthur. He cropped up in sources of Celtic mythology, like the Mabinogion from Wales, and you could trace Arthur in the genealogies of the Welsh kings. An inscription bearing the name ARTORIUS had even been found at one of Arthur’s supposed strongholds. But by the ninth century, the myth was spreading. What Welsh prince wouldn’t want his name linked with Arthur? And that ARTORIUS inscription, on closer inspection, looked more like ARTOGNUS . . .