Born in Cento, Giovanni Francesco Barbieri, called il Guercino (1591–1666), was one of the most prolific, virtuosic, and inventive draftsmen of the seventeenth century. This essay, based on over four decades of research, offers new insights into Guercino’s idiosyncratic creative process as seen through his numerous preparatory drawings. Unwilling to tie himself down to a fixed idea, he was reluctant to give patrons a full compositional sketch in advance of submitting to them the finished, commissioned painting. In fact, Guercino made rather few overall designs compared to many of his contemporaries. He tended to work out his ideas in smaller units and ‘close-up studies’, pulling everything together in his mind’s eye at the painting stage. This is one of the reasons his extant sketches do not match their painted counterparts: he was making changes right up to the end of a project.

At the heart of the study is an analysis of nearly all the known preparatory sketches for Guercino’s lateral painting of 1632 for the Fiordibelli Chapel in Reggio Emilia depicting the Martyrdom of Saints John and Paul (a canvas now in Toulouse). This discussion proposes a new way of considering the problem of sequence in Guercino’s sketches, focussing especially on his concepts of narrative, modality, and decorum.

Finally, Guercino’s seemingly endless search for compositional and figurative solutions in his drawings is put into the context of his seemingly antithetical pricing system for his pictures, for which he charged by the full figure, half figure, or head.