Before beginning work on Reni’s panel, the restorer had gone to Rome to view the Caravaggio again. Reni had obviously borrowed from his competitor-most strikingly, his technique of using chiaroscuro to infuse his figures with life and lift them dramatically from the background-but there were many differences between the paintings, too. Where Caravaggio had placed the inverted cross diagonally through the scene, Reni positioned it vertically and in the center. Where Caravaggio had shown the agonized face of Peter, Reni deftly concealed it. What struck the restorer most was Reni’s depiction of Peter’s hands. In Caravaggio’s altarpiece, they were already fastened to the cross. But in Reni’s portrayal, the hands were free, with the right stretched toward the apex. Was Peter reaching toward the nail about to be driven into his feet? Or was he pleading with God to be delivered from so terrible a death?

The restorer had been working on the painting for more than a month. Having removed the yellowed varnish, he was now engaged in the final and most important part of the restoration: retouching those portions damaged by time and stress. The altarpiece had suffered substantial losses in the four centuries since Reni had painted it-indeed, the midrestoration photos had sent the owners into a blue period of hysteria and recrimination. Under normal circumstances, the restorer might have spared them the shock of seeing the painting stripped to its true state, but these were hardly normal circumstances. The Reni was now in the possession of the Vatican. Because the restorer was considered one of the finest in the world-and because he was a personal friend of the pope and his powerful private secretary-he was allowed to work for the Holy See on a freelance basis and to select his own assignments. He was even permitted to conduct his restorations not in the Vatican ’s state-of-the-art conservation lab but at a secluded estate in southern Umbria.