Roberto Longhi was the first to relate this drawing to the left-hand panel of the altarpiece of Saint Eligius in the church of S. Maria dei Mendicanti, Bologna, A. Cera, La pittura emiliana del '600, Milan, 1982, Cavedone, no. 14. Laura Giles dates the altarpiece to circa 1624-25, and the drawing to an earlier date. There are only few differences between the drawing and the picture: the position of the horse has been reversed and the forge in the background has been removed. A preparatory drawing for the head of Saint Eligius is at Windsor Castle, O. Kurz, Bolognese Drawings of the XVII & XVIII Centuries in the collection of Her Majesty the Queen at Windsor Castle, London, 1955, no. 84, illustrated.
Saint Eligius (circa 588-660) was a goldsmith and later became Bishop of Noyon. The legend tells how he replaced the shoe of a kicking horse possessed by the devil by cutting off the horse's leg, changing the shoe and placing the leg back on the horse. Saint Eligius is the patron saint of Bologna and is often represented in Bolognese art.