VATICAN CITY — The Vatican Museums on Thursday unveiled the last and most important of the restored Raphael Rooms, the spectacularly frescoed reception rooms of the Apostolic Palace that in some ways rival the Sistine Chapel as the peak of high Renaissance artistry.
A decade-long project to clean and restore the largest of the four Raphael Rooms uncovered a novel mural painting technique that the superstar Renaissance painter and architect began but never completed: the use of oil paint directly on the wall, and a grid of nails embedded in the walls to hold in place the resin surface onto which he painted.
Vatican Museums officials recounted the discoveries on Thursday in inaugurating the hall, known as the Room of Constantine, after the last scaffolding came down. The reception room, which was painted by Raphael and his students starting in the first quarter-century of the 1500s, is dedicated to the fourth-century Roman emperor Constantine whose embrace of Christianity helped spread the faith throughout the Roman Empire.
''With this restoration, we rewrite a part of the history of art,'' Vatican Museums director Barbara Jatta said.
Pope Julius II summoned the young Raphael Sanzio from Florence to Rome in 1508 to decorate a new private apartment for himself in the Apostolic Palace, giving the then 25-year-old painter and architect a major commission at the height of his artistic output.
Even at the time, there were reports that Raphael had wanted to decorate the rooms not with frescoes but with oil paint directly on the wall, to give the images greater brilliance. The 10-year restoration of the Rome of Constantine proved those reports correct, said Fabio Piacentini, one of the chief restorers.
Vatican technicians discovered that two female figures, Justice and Courtesy and located on opposite corners of the hall, were actually oil-on-wall paintings, not frescoes in which paint is applied to wet plaster. They were therefore clearly the work of Raphael himself, he said.
But Raphael died on April 6, 1520, at the age of 37, and before the hall could be completed. The rest of the paintings in the room were frescoes completed by his students who couldn't master the oil technique Raphael had used, Jatta said.