Pont “Nut job. That was the word on Jacopo Pontormo, the finest religious painter in 16th-century Florence and guru of Mannerism, a late Renaissance style that crossed Michelangelo’s pumped-up classicism with Raphael’s skin-so-soft version.

Pontormo wasn’t winsome nuts; he was spooky nuts. He lived alone in a room reached by a ladder that he could pull up after him. He was phobic about death. Mention the word and he fell apart. Excruciatingly self-obsessed, in the four years before he died, in 1556 or 1557, he kept a diary, often hour by hour, of every thought he had, every twinge of pain he felt, every morsel of food he ate. He was, in short, an exposed nerve for whom art provided the only protective covering.”

Holland Cotter reviews “Pontormo, Bronzino and the Medici: The Transformation of the Renaissance Portrait in Florence,” an exhibition at the Philadelphia Museum of Art, here in the New York Times.