The Art Archive / Museo Nazionale Terme Rome / Dagli Ort

Snakes encircle Asklepios’s head in this first-century A.D. Roman mosaic from the floor of an imperial villa. Snakes were sacred to Asklepios, who used them as siphons to drain the wounds of his patients. Asklepios is often depicted with snakes entwined around his head, leg or staff—an image, known as the caduceus, that has become a symbol of modern medicine.