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. According to legend, the river god Alpheus fell in love with one of Artemis's nymphs Arethusa. Since she was a virgin, and wished to remain so, Alpheus's advances were repulsed. To escape him she fled to Syracuse with the river god in hot pursuit. Fearing capture Arethusa called upon Artemis for help, who proceeded to turn the nymph into a river. However, even in this form she did not elude Alpheus, who mingled his waters with hers to become eternally united. This beautiful girl is best known from coins of Syracuse. The profile on this lovely intaglio is so delicate there is little distinction between male and female. Coins from the Sicilian city of Leontini show the bust of Apollo similar to this one, and may have served as a model for the engraver. Whether river nymph or sun god, the deity depicted shines with an endearing warmth and eternal beauty.