This is the original drawing that was used for the engraving. In the "Inventory of the drawings owned by Mr. Cav. Paolo Toschi made by himself", probably drawn up after the engraver's death (Museo Glauco Lombardi, Toschi archive, cont. 55, fasc. 42), its is mentioned a watercolor portraying Ireneo Affò , which is almost certainly to be identified with this artwork.
You are all set!
Your first Culture Weekly will arrive this week.