The seventeenth-century Roman artist Girolamo Troppa was something of a chameleon, working in several different styles. Many of his works have been misattributed to his contemporaries, but he often signed his drawings, including this one. The two main figures here are Jupiter, identified by the thunderbolts he grasps in his left hand, and his wife, Juno, shown with her customary peacock. The cow seen from behind in the distance is the key to the story; it is probably Io, Jupiter’s lover, whom he transformed into a cow to protect her from Juno’s wrath. The low viewpoint of the drawing could indicate that the composition was designed to decorate a ceiling. The cows, sheep, and goats depicted on the verso cannot be linked to any specific painting. These animals might have been studies for the background elements of a painting, or they could have been an unrelated drawing exercise, perhaps inspired by the Io story on the recto. Similar beasts are found in other paintings by Troppa, who frequently engaged pastoral themes.