Stephano was discovered on July 18, 1999 by Brett Gladman, Matthew Holman, John J. Kavelaars, Jean-Marc Petit, and Hans Scholl using the Canada-France-Hawaii Telescope at the Mauna Kea Observatory on the island of Hawaii. They discovered Prospero and Setebos at the same time.
About 20 miles (32 kilometers) in diameter (assuming an albedo of 0.04), Stephano is a small, dark moon which orbits Uranus in the opposite direction from the regular satellites and the planet's rotation (a retrograde orbit). Its orbital characteristics are similar to those of Caliban, suggesting a common origin.
How Stephano Got its Name
Originally called S/1999 U2, Stephano was named for a boisterous butler of King Alonso in William Shakespeare's play, "The Tempest."