Giovanni Francesco Barbieri, called Guercino

As Nicholas Turner has kindly confirmed to the present owner, this previously unknown, finely detailed drawing by Guercino, with its clarity of form and subtle modulations in the application of the artist's preferred medium of red chalk, appears to be a study for his early painting of the Sibyl Hellespontica, in the collection of the National Trust, at Ickworth House, Suffolk.¹ The attribution to Guercino of this painting was not always accepted, but in recent times it has come to be considered a fully autograph work. Both the drawing and the painting must date from the second half of the 1620s, when the influence of Guercino's Roman period (1621–23) was still apparent in his work. 

In terms of handling, the drawing is closely comparable with red chalk studies for the series of frescoes of Seated Sibyls, which Guercino painted in 1627 at the base of the drum of the cupola of Piacenza Cathedral. Turner compares this drawing in particular with two such sheets, in Oslo and Budapest.²    

1. Ickworth, Suffolk 1998 [The National Trust: Nino Strachey] 1998, p. 13 http://www.nationaltrustcollections.org.uk/object/851988

2. Oslo, Nasjonalgalleriet, inv. no. NG.K&H.B.15244; Budapest, Museum of Fine Arts, inv. no. 2318