Only later did Nini find that the rooms that lay beyond that bricked-up door had been used as a prison cell and torture chamber during the Roman Inquisition. The cell, which was barely nine feet across, was covered in graffiti - code words and pictures that had been scratched into the wall.

"The Da Vinci Code was nothing compared with this," he tells me. "This was real."

I FIRST MET NINI on a cold, billowing March evening at a café in Narni, a walled medieval city built on a hilltop above the Nera River and located about 40 miles north of Rome, in the central Italy region of Umbria. The city dates to at least 600 BC and was destroyed and rebuilt more than once. It was called Narnia in Roman times, and although there is no evidence that the writer C.S. Lewis ever visited it, the town fathers wonder if it was in any way an inspiration for Lewis's The Chronicles of Narnia.

Nini looks like the stereotypical archaeology professor: He's tall and slender, with gray hair and an impassioned way of speaking.

"Give me 15 minutes of your time, and I will show you something that will surprise you," he told me.

I followed him through snow flurries, walking up the street to a church and then down several flights of steps to a locked door. When my eyes finally adjusted to the flickering light on the other side, I saw faded and peeling frescoes, painted by unknown Umbrian artists in the thirteenth and fourteenth centuries. A thighbone protruded from the floor - I later learned that it likely belonged to an unknown nobleman who was buried beneath the chapel in hopes of his obtaining a hastened trip to paradise.

"This was discovered by six boys," he said to me in Italian. When I asked who they were, he responded, "My friends and me."