It hung in the manner of Michelangelo’s Pieta, with the fingers pointing allegorically toward the corner of the funerary stone. For several days, Gabriel had been attempting to repair a series of abrasions along the knuckles. He was not the first artist to struggle over the composition; Caravaggio himself had painted five other versions before finally completing the painting in 1604. Unlike his previous commission-a depiction of the Virgin’s death so controversial it was eventually removed from the church of Santa Maria della Scala- The Deposition was instantly hailed as a masterwork, and its reputation quickly spread throughout Europe. In 1797, the painting caught the eye of Napoleon Bonaparte, one of history’s greatest looters of art and antiquities, and it was carted over the Alps to Paris. It remained there until 1817, when it was returned to the custody of the papacy and hung in the Vatican.

For several hours, Gabriel had the lab to himself. Then, at the thoroughly Roman hour of ten, he heard the snap of the automatic locks, followed by Enrico Bacci’s lumbering plod. Next came Donatella Ricci, an Early Renaissance expert who whispered soothingly to the paintings in her care. After that it was Tommaso Antonelli, one of the stars of the Sistine Chapel restoration, who always tiptoed around the lab in his crepe-soled shoes with the stealth of a night thief.

Finally, at half past ten, Gabriel heard the distinctive tap of Antonio Calvesi’s handmade shoes over the linoleum floor. A few seconds later, Calvesi came whirling through the black curtain like a matador. With his disheveled forelock and perpetually loosened necktie, he had the air of a man who was running late for an appointment he would rather not keep. He settled himself atop a tall stool and nibbled thoughtfully at the stem of his reading glasses while inspecting Gabriel’s work.

“Not bad,” Calvesi said with genuine admiration. “Did you do that on your own, or did Caravaggio drop by to handle the inpainting himself?”