Even as he sleeps, this naked Saint Jerome ripples with energy, as does his billowing blanket. Coupled with his quick, fertile imagination, Parmigianino's mastery of pen, ink, wash, and heightening gives this rendering a refreshing spontaneity. The artist crafted the dynamic composition from lively, fluid, yet never superfluous lines and modulated the wash with the touch of a brush for lighter or darker tones. He used white heightening, which can easily overpower a drawing, in a precise, economical, and balanced manner.
Parmigianino made this drawing in preparation for an altarpiece, The Vision of Saint Jerome , of about 1526, now in London's National Gallery, but the painted figure ended up less powerful and older than this vigorous creature. His study of monumental ancient sculpture and Michelangelo's art led to this figure's expansiveness and muscularity.
A later collector may have cut the sheet at the top, eliminating parts of the head and arms.