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. To the ancient Roman, especially during the imperial period, there was a close connection between deities, emperors and their wives. After his death the emperor Antoninus Pius (reigned 138-161 A.D.) was deified by 'universal consent'. Of course, the quality and character of the ruler did influence the posthumous honors. On this fine intaglio the portrait of a dignified man is shown facing left, with a curled beard and wearing a tight fitting cap (which may be a manner of representing a diadem surrounding smoothed hair). He is obviously someone of noble character, and does in fact bear a strong resemblance to Antoninus Pius. The image on this intaglio is striking whether it depicts a god or man.