The art of glyptics, or carving on colored precious stones, is probably one of the oldest known to humanity. Intaglios, gems with an incised design, were made as early as the fourth and third millennia BC in Mesopotamia and Aegean Islands. They display a virtuosity of execution that suggests an old and stable tradition rooted in the earliest centuries. The tools required for carving gems were simple: a wheel with a belt-drive and a set of drills. Abrasives were necessary since the minerals used were too hard for a metal edge. A special difficulty of engraving intaglios, aside from their miniature size, was that the master had to work with a mirror-image in mind. Aesculapius was the god of medicine, son of Apollo, and raised by the Centaur Chiron who taught him medicine. His skills in this art became so remarkable he was able to revive the dead using the blood from the Gorgon Medusa. Worried by so many resurrections, Zeus sent a thunderbolt to kill Aesculapius, who was then transformed into a constellation. In art he is depicted as a venerable old man, as on this very lovely intaglio, with his long beard and elegantly curled hair. The cult of Aesculapius flourished at Epidaurus in the Peloponnese where a school of medicine was founded. It's most famous pupil being the great physician Hippocrates. On the lower left corner is a caduceus with a snake curling up a wand, used for centuries as the symbol of medicine. Perhaps this intaglio was designed for a physician of ancient Rome; surviving the centuries through its own unique magic.