Galileo Galilei discovered this moon in 1610. Simon Marius suggested the name "Ganymede" soon after. In Greek mythology, Ganymede was Zeus' cup-bearer. This name and the names of the other Galilean satellites were not favoured for a long time, and were not put into common use until the mid-20th century. Instead, it is simply referred to by its Roman numeral designation (a system that was introduced by Galileo) as or as the "third satellite of Jupiter". Ganymede is the only Galilean moon of Jupiter named after a male figure.