The story of the water-nymph Egeria belongs among the myths surrounding the origins and early history of Rome. According to Ovid in the Metamorphoses, Egeria was the wife and adviser of King Numa Pompilius. She met the king in a grotto in which she lived outside the gates of the city, in a shady valley not far from the Via Appia. It was believed to be the grotto depicted here, which travellers visited because of its literary associations and which artists had painted frequently since the seventeenth century.