If you look closely at the statue you see joints everywhere. Michelangelo must have really tried to make it impossible for anyone to repair it.
He smashed left and right, as if by destroying wholesale he might remove any clue as to the part that really vexed him. He destroyed both far-along carved limbs, such as Christ’s beautiful left arm, and only sketched-out ones, such as the long, right arm of the other Mary. In that limb you see at least four joints.
Cacagni’s reconstruction of the group, though Vasari sighs about it, was the least of the harm he did, since he had Michelangelo’s wax models to guide him and many of the pieces of the puzzle before him. His real sacrilege was his picking up a chisel and carving on the figures and filing and polishing them with an aim to finish—that is, in his mind, to improve it. All the polishing is his doing, of course. That includes the shining of that offensively thin leg. Was it he who made it so thin? Unfortunately, no one can know that. But that he worked at all on it allows us to refuse to consider the Master responsible. For all we know, Cacagni removed the last eighth of an inch while filing and sanding it down. It wasn’t too thin on the little model.
Comparing the stone Pietà with the wax model, you see several other differences; and the biggest is that faulty figure on Christ’s right. Condivi saw the Pietà while Michelangelo was still working on it, before he broke it; and he called the figure “one of the Marys”. What is striking in the marble version is its small size. It seems to be modelled according to another scale. It is very oddly proportioned and childish compared to the great Christ and the other Mary. Who reduced its size—Cacagni or Michelangelo?
The wax model doesn’t show this diminuition of the Mary. She is full-sized there and stands taller. Her head reaches as high as Christ’s lifted shoulder, as high as the Virgin’s head opposite, and balances it off. That made sense.
In the stone version she is shorter but her arm, which had to reach low in order to brace up Christ’s thigh and keep consonance with Michelangelo’s design, is just as long as in the wax model. Now it is perhaps too long. It is certainly strained and graceless. Christ’s hand, which originally fell to her waist, now reaches only her shoulder. Her stiff, pillar-like thigh—that’s also too long. What are we to think? Did Cacagni reduce the top half of the figure?
That would explain the triteness of the shoulders and of the head, which are particularly unexpressive. When he saw the group, Condivi was impressed by the “wonderful expression” of the figures. In the Pietà that we see it is hard to be impressed with this Mary’s expression because she doesn’t have any. Surely Cacagni chiselled it and polished it away.
Notice one more thing: Mary’s left leg, or rather, her thigh, since she is kneeling, is out of sight. In Michelangelo’s model it was side by side with her other one and right behind Christ’s lower leg, touching it, perhaps relieving with the contingent lines of a fold or two the long diagonal slash it made. In the marble statue, instead of a knee and cloth, there is only a dark hole. And that hole is partly responsible for setting off the skinny leg, exaggerating its nakedness, hiding with its shadow some of its flesh, such as the calf. Why did Cacagni dig out the marble from behind it? Perhaps to justify a new movement, a new posture, he had created when he lowered Mary’s upper half. She now leans outwards, away from Christ’s body.
Conclusion: We are justified in attributing all the bad, all the errors of this Pietà, to Tiberio Cacagni.
But what if some of them weren’t his? Could Michelangelo himself have made one or two?