Gylippus is a Spartan general of the 5th century BCE; he was the son of Cleandridas, who was the adviser of King Pleistoanax and had been expelled from Sparta for accepting Athenian bribes in 446 BCE and fled to Thurii, a pan-Hellenic colony then being founded in the instep of Italy with Athenian help and participation.

His mother may have been a helot, which meant he was not a true Spartiate but a mothax, a man of inferior status.

Despite this, however, from an early childhood he was trained for war in the traditional Spartan fashion and on reaching maturity had been elected to a military mess, his dues contributed by a wealthier Spartiate patron.

For an individual of marginal origins, war was an opportunity to gain honor and eminence.