This exceptionally large drawing is related to a picture (fig. 1) of the same subject signed and dated 'In Bologna Caietanus Gandolfi 1766' in the Museo Civico, Piacenza (P. Bagno, I Gandolfi. Affreschi, dipinti, bozzetti, disegni, Bologna, 1992, no. 219).
The scene is taken from the Odyssey. Ulysses has reached the island of Aeaea, home of the enchantress Circe. She has transformed his companions into swine and the hero visits her to retrieve his men. On his way to the sorceress's castle he has met Mercury who has warned him against Circe's magic and given him an antidote to her magic potion. Mercury also advises Ulysses to draw his sword and threaten Circe's life when she tries to transform him with her wand. Ulysses follows these instructions and the enchantress becomes enamoured of the one man able to resist her spells and charms. Ulysses then convinces her to restore his men to human form, and he and his entire crew spend a full year banqueting as Circe's pampered guests.
There are marked differences between the drawing and the picture in Piacenza. First of all, the composition is studied in reverse, a common studio practice in Bologna. The game of inversion is here pushed a degree further with the figure of Ulysses shown frontally, when, in the picture, the hero appears with his back turned. Conversely, Mercury is seen from the rear on the present sheet as on the canvas he is represented frontally. Similar inversions are applied to the figures of men transformed into swine in the foreground.
Although there are some pentimenti (noticeable, for example, in the drapery hanging from the bed), the drawing's size, its highly finished quality as well as its technical virtuosity, and subtle but extensive use of white heightening may indicate that it was intended as an independent work. This hypothesis seems confirmed by the existence of a smaller (267 x 206 mm.) drawing in the Los Angeles County Museum (fig. 2) (B. Davis, Master Drawings in the Los Angeles County Museum of Art, Los Angeles, 1997, no. 37). Vivaciously executed in brown ink and dark grey wash over traces of black chalk it is a direct study for the picture with few differences.