Ovid
The Metamorphoses of Ovid, Book I (Fable. 5)
The Giants having attempted to render themselves masters of heaven, Jupiter buries them under the mountains which they have heaped together to facilitate their assault; and the Earth, animating their blood, forms out of it a cruel and fierce generation of men.

And that the lofty realms of æther might not be more safe than the Earth, they say that the Giants aspired to the sovereignty of Heaven, and piled the mountains, heaped together, even to the lofty stars. Then the omnipotent Father, hurling his lightnings, broke through Olympus,36 and struck Ossa away from Pelion, that lay beneath it. While the dreadful carcasses lay overwhelmed beneath their own structure, they say that the Earth was wet, drenched with the plenteous blood of her sons, and that she gave life to the warm gore; and that, lest no memorial of this ruthless race should be surviving, she shaped them into the form of men. But that generation, too, was a despiser of the Gods above, and most greedy of ruthless slaughter, and full of violence: you might see that they derived their origin from blood.

Footnotes:

36. Olympus.]—Ver. 154. Olympus was a mountain between Thessaly and Macedonia. Pelion was a mountain of Thessaly, towards the Pelasgic gulf; and Ossa was a mountain between Olympus and Pelion. These the Giants are said to have heaped one on another, in order to scale heaven.