In the beginning, there was nothing in this world as it was in a state of nothingness otherwise called Chaos. Chaos may be identified as a god for born out of it was Gaia, the Earth. Not only Gaia was out of Chaos as Nyx (the goddess of night), Tartarus (the Underworld) and Erebos (the darkness of the Underworld) were also born of Chaos.

As time went by, Gaia bore a son whom she named Uranus, the Sky, without a lot of thought, Gaia had sexual intercourse with Uranus making him her husband. Due to their sexual intercourse, Gaia and Uranus had twelve children who were later called the Elder Titans.

The Elder Titans were the first generation of Titans which were the children of Gaia and Uranus. These children included Okeanos, Tethys, Koios, Phoebe, Hyperion, Theia, Kreios, Iapetos, Themis, Mneosyne, Kronos and Rhea.

Gaia also gave birth to cyclops and monsters called the hundred handed ones. These monsters disgusted Uranus giving him no other choice but to throw them into Tartarus. Angered with her husband's judgement, Gaia began to plot against him, she sought for the support of her children - the Titans but none answered her call except Kronos. Gaia made a weapon which she handed to Kronos to cut off his father's genitals making him unable to make anyone else pregnant. I believe she did this so that her husband would learn never to destroy what he sowed. As his mother planned, Kronos was able to cut of the genitals of his father and as he did this, he threw Uranus into the ocean. From the blood flowing out of Uranus' genitals into the ocean, Aphrodite - the goddess of love, pleasure, beauty and procreation was formed. 

Stolen novel; please report.

With the death of Uranus, even though Kronos was the youngest son, with the support of Gaia he rose to become the leader of the Titans taking his father's place. The gods must have been lonely for them to marry their own siblings as Kronos married his own sister, Rhea, ushering in the first generation of Olympian gods.