Giovanni Francesco Barbieri, called Il Guercino

Possibly Casa Gennari

The drawing has some foxing and some brown discolouration, mainly in the edges and the blank background above. There are some small paper losses due to worms or insects, and some surface losses along the left edge. A similar surface loss in the drapery near the saint's throat, has been touched in. The sheet is backed with linen.
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This impressive study of St. Peter is one of a number of bust- or half-length representations of saints which were made by Guercino throughout his career. See, for example, the series of Four Evangelists in the Staatliche Gemäldegalerie, painted by Guercino circa 1615, or the 1650 Saint Peter weeping in the Cassa di Risparmio, Bologna.¹  Guercino's use of such apparently simple compositions created powerful devotional images, in which the contemplation of the saint became more personal and direct. 

Nicholas Turner dates the drawing to the 1640s or 1650s and notes that the high degree of finish and contained composition indicate that it was made for its own sake, rather than being preparatory for a painting.  Two comparable presentation drawings by Guercino, in red chalk and from the same period, are Diana Burning the Instruments of Love, in a private collection, New Haven, Connecticut, and a study of the Magdalen Praying in a Landscape, in the Morgan Library, New York.²

The fact that the sheet is laid down on canvas suggests that it may originate from Casa Gennari, where many of Guercino's drawings, as well as those by other artists from his collection and by his nephews Benedetto and Cesare Gennari, were similarly laid down in order to be hung on the walls.  For further information on the Guercino drawings that passed to Casa Gennari, see D. Mahon and N. Turner, The Drawings of Guercino in the Collection of Her Majesty the Queen at Windsor Castle, Cambridge 1989, pp. XVII- XXII.

1. See D. M. Stone, Guercino Catalogo completo dei dipinti, Florence 1991, pp. 28-29, 264-5, cat. nos. 10-13, 256 
2. See D.M. Stone, Guercino Master Draughtsman, Cambridge, Mass. 1991, nos. 60, supplement no. 136, pp. 138-9, 220, plate A