But the authors contend that there are insults in plain sight. They point to the fresco of the Prophet Zachariah, which they believe is a likeness of the pope. Could Michelangelo have been so angry with Julius that he would paint an obscene hand gesture into this panel? Blech says one of the putti is doing the Renaissance equivalent of giving the pope's portrait "the finger."
"There's no doubt about it," he said. "This little putti, this beautiful little angel, is giving the finger not to Zachariah, but to Pope Julius."
He says that the ceiling is full of insults and that the hand gesture is seen again in the fresco of the Cumaean sibyl.
"It happens a second time," he said. "Twice, that's a statement."
But scholars are skeptical.
"I would call them jokes … but we should never make a joke the center of interpretation," said Wallace.
Lev does not see the gesture at all.
"You do not see what they purport you see," Lev said. "It is something that could be, with a lot of imagination and some ill will, perceived as a rude gesture. But really it could also be one Putto caressing the cheek of another Putto."
Scholars may disagree about Michelangelo's messages in the ceiling, but it's hard to argue with the ceiling as a masterpiece.
"It's one of the greatest works of mankind that was ever produced, and it's one of the greatest treasures of art," said Nesselrath.