Nicholas Turner has dated this drawing on stylistic grounds to the 1640s. It is rather close to Guercino's painting of Isaiah, Head and Shoulders, Reading a Letter, commissioned by the Marchese Cospi and paid for on 20 November 1648 (Private Collection; see Luigi Salerno, I Dipinti del Guercino, Rome 1988, p. 327, no. 255, reproduced). A red chalk study by Guercino, in a private collection, is related to that painting (see David M. Stone, Guercino, Padua 1991, p. 224, no. 184, reproduced pl. E).