EditThe Dawn Age
From the beginning of time, Westeros was populated by the mysterious, diminutive, humanoid children of the forest, gifted with many supernatural powers, who for time-uncounted lived alone throughout the continent of Westeros, with the exception of the Giants (and maybe one other race, if the legend of the Seastone Chair on Old Wyk in the Iron Islands is true). They worshipped the nameless gods of forest, stream, and stone, and lived off of the land. It's unknown how long the children lived alone in Westeros, nor where they themselves came from. The oldest records available only relate to arrival of the First Men to the continent, from the eastern continent of Essos, about 12,000 years ago.
The First Men crossed into what would be called Dorne from the eastern continent, using the land bridge that connected the continents. They came bearing weapons of bronze and shields of boiled leather, the first horses, and their own gods. They swept through the lands of the children, cutting down and burning their sacred weirwoods to clear land for themselves. Outraged by the destruction of their homeland, the children took up arms.
It’s believed the wars between the children and the First Men went on for two thousand years and though the children fought fiercely, the war went in the favor of the more numerous, larger, stronger, and more technologically advanced First Men. It's said that during that time, the children used powerful magic in a futile attempt to end of the invasion, breaking the Arm of Dorne. Eventually wise leaders of both races forged the Pact at the Isle of Faces, which ended the war, marking the end of the Dawn Age and the beginning of the Age of Heroes.