Although most moons in our solar system are named after figures in Greek and Roman mythology, Uranus's moons get their names from English literature. 25 of the 27 are named after Shakespeare characters, with the majority of those taking their names from "The Tempest." The remaining two, Belinda and Umbriel, are named after characters invented by 18th-century English poet Alexander Pope. (One moon, Ariel, has a name that appears in both authors' work.) Ophelia and Cordelia are known as "shepherd moons." They keep Uranus's brightest ring intact by corralling its materials with their gravitational pull.