For the art historian Michael Hirst it is “one of the most familiar in the history of art”—the gesture Mary makes with her left hand in Michelangelo’s Pietà (1498–99) in Saint Peter’s Basilica in Rome. That sculpture, commissioned by a French Cardinal for his burial site, a chapel in the old Saint Peter’s, was the twenty-four-year-old artist’s breakout work, one that instantly established his fame throughout Italy. Yet perhaps because of its familiarity, Mary’s gesture is one of the least examined aspects of Michelangelo’s art. “We are prone to take the Pietà for granted as we do all the greatest works of art,” wrote Sir John Pope-Hennessy, while Howard Hibbard noted that the sculpture is “one of those famous works, like the Mona Lisa or the Venus de Milo, that it is almost impossible to see afresh.” True enough, for in the vast Michelangelo literature, Mary’s gesture receives scant mention. When it is discussed, the outswung arm and open hand are said to betoken two things: her final acceptance of God’s will in the sacrifice of her son, and the artist’s desire, through Mary’s simultaneous act of revelation, to include the viewer in the implied narrative of Christ’s Passion and maternal grief. No argument there. But looking afresh at this canonical masterpiece of Renaissance sculpture forces two conclusions: That the manifold implications of those observations have never been explored, and that Mary’s left hand tells us not two things, but five.

The Pietà as a subject had