Uranus threw his rebellious sons, the Cyclopes, into Tartarus and then fathered the Titans upon Mother Earth. But she persuaded the Titans to attack their father and led by the youngest, Cronus, they surprised Uranus in his sleep. When Cronus castrated Uranus with a flint sickle, some drops of blood fell upon Mother Earth, who bore the three Erinnyes, furies who avenge crimes of parricide and perjury.
The Titans freed the Cyclopes and appointed Cronus ruler of the Earth. No sooner was he in charge or he threw the Cyclopes and the Hundred-handed Ores (back) into Tartarus.
Robert Graves, The Greek Myths. Complete Edition.