Originally the personification of the rainbow, Iris later became known as the swift golden-winged messenger of Zeus and Hera. She was frequently sent to the earth with messages for mortals, and the rainbow was the bridge by which she travelled.

The piece was written in 1984. It is in arch form and consists of five sections played without a break. The first resembles a quick perpetuum mobile, the second is slower and more chordal and the central section is very slow. The fourth and fifth are variations of the second and first respectively.