Andrea Commodi, The Fall of the Rebel Angels

Commodi’s ‘back of an envelope’ sketch was shaped by the arbitrary confines of the letter’s address and red wax seal, still visible in the upper right-hand corner of the paper. The angels twist around to accommodate them. It is one of many studies by Commodi for an unexecuted fresco commissioned by Pope Paul V around 1616 for the chapel of the Palazzo Quirinale in Rome; another three are on the backs of letters.