When Uranus refused to allow his children to be born, Gaia appealed to her unborn children for help. Her youngest son, the Titan Cronus was the only one, who heeded her call.
With a sickle made of adamantine, he castrated his father. From the blood sprung the Furies and Giants, and Aphrodite rose from the foam created by the union of the severed penis and the sea.
With his Uranus now deposed, Cronus assumed the role of king. The time of Cronus' rule was known as the Golden Age, when men lived a life free from vice and toil. He took his sister Rhea as his wife, and began to have children.
Unfortunately, Cronus, whom Hesiod describes as a 'crooked schemer,' repeated the folly of his father. Having learned that he was fated to be overthrown by his children, Cronus swallowed every child as soon as Rhea had given birth. Like her mother, Rhea grieved over the fate of her children. Rhea turned to her parents for help, and Gaia gave to her a plan.
When Zeus was about to be born, Rhea flew down to Earth. In a Cretan cave, she hid her youngest son. Picking up a rock, she returned to Cronus' side. Without examining his newest 'child' Cronus swallowed the stone whole.
When Zeus was old enough, he returned and forced Cronus to vomit up his brothers and sisters, as well as the stone Cronus had thought to be his son. Falling to the Earth, the stone came to rest at Delphi, where the Oracle of Apollo was located. With his brothers freed, Zeus and the Gods battled the Titans in the Titanomachy. Thanks to the help of their uncles the Cyclopes and Hecatoncheires, Cronus and the Titans were eventually defeated.
The Romans related Cronus to their Saturn, a god of grain. This was perhaps because both the Greek Cronus and the Roman Saturn were related to the sickle.