A drawing of Syrinx metamorphosing into reeds as Pan stands amazed, on the left. A reclining river god watches in the centre foreground, as water flows from the jar he leans upon. The nymph Syrinx was fleeing the amorous pursuit of Pan when she found her escape blocked by a river. She prayed to the gods to be saved and was transformed into a stand of reeds. In 1661 Castiglione sent a sketch of Pan and Syrinx to the Duke of Mantua for approval before beginning work on a canvas; this drawing may be related to that commission, though the fluid handling would place it a few years earlier than that date. Castiglione dealt with this subject in another drawing, RCIN 903994. A variation on the theme, Nymph surprised by satyrs, is in the Victoria and Albert Museum (Dyce 347).