A drawing of the head of St Petronius in Reni's painting of the Madonna and Child adored by Saints (the Pala delle Peste), in the Pinacoteca, Bologna. The painting was executed as a votive standard to be displayed for three days each year in thanks for the relief of Bologna from the plague of 1630, and carried through the streets of the city each 10 December on the feast of the Madonna of the Rosary (the Compagnia della Madonna del Rosario had its altar in the church of San Domenico). 

The drawing was catalogued by Kurz (in K(B)) as a study for the painting. It was considered by C. Johnston (The Drawings of Guido Reni, PhD thesis, 1974, p.175) and V. Birke (Guido Reni: Zeichnungen, Vienna 1981, p.166) as probably a copy, and indeed it seems to be a good copy by a pupil after an original drawing by Reni (rather than a copy after the painting).