Some friends of mine decided to renew their wedding vows for their fifteenth anniversary, and asked me to make the rings—I was especially honored to be a part of the celebration as I had been at their wedding in the first place. The groom had hatched the idea beforehand, and he had some specific ideas. The rings had to be flat, because his bride is a professional pianist and she needed something that wouldn't hit the keys as she played. They had to be tough and dent-resistant for the times that she does hit the keys, so we used 10 karat gold because it's a harder alloy than 14 or 18 karat gold.
As noted above, the bride is a professional musician. She's also part Greek, and these two attributes inspired the groom's idea for the design. The letters etched into the surface of the band are the first line of the Seikilos Epitaph, which is the world's oldest known fully-complete musical piece, including both lyrics and music. The first line, "Ὅσον ζῇς, φαίνου" (Hoson zês, phainou) translates to "when you live, shine"—and is, in my experience, a perfect summation of their relationship. The outlined letters on these bands are based on rubbings of the stele on which the epitaph was found. Below is a YouTube video with a fantastic arrangement of the song as performed by the San Antonio Vocal Arts Ensemble, which also contains pictures of the original stele.