The oldest of the true histories, insofar as the true histories reach so far, tell that the children of the forest held all Westeros before ever a man set foot upon it, a small and secretive folk who wove no crowns and raised no cities but kept to their weirwood groves and worshipped nameless gods of stream and stone and tree. When the First Men came out of the east across the land bridge of the Arm of Dorne, bearing bronze swords and great leathern shields and riding horses, they cleared the forests for their fields and hewed the faces from the weirwoods, and the children, who loved those trees above all things, went to war against them. So the tale is told at the Citadel, though how much is history and how much the ornament of singers no learned man will swear. The children fought with weapons of dragonglass and with the wild beasts of the wood, and their greenseers, it is said, could speak through the faces of the trees and see across leagues; yet the First Men were larger, more numerous, and armed with bronze, and the war between them ground on across two thousand years and more.
The songs remember that in their desperation the children called upon the greenseers to work a great magic, the hammer of the waters, and that the sea rose up and shattered the Arm of Dorne into the broken chain of islands men now call the Stepstones, that no more men might cross; and that a second such working drowned the land between Westeros and Essos where later the Neck would flood into swamp. Whether any such sorcery was truly done, or whether the drowning of those lands was only the slow work of tide and time that the singers have since dressed in wonder, Maester Yandel and his brothers do not presume to say. What the histories agree upon is the ending. Weary of a war that neither side could win, the First Men and the children came together upon the Isle of Faces in the great lake called Gods Eye and there sealed the Pact, granting the open lands to men and the deep forests to the children, and carving a face into every tree upon the isle so that the gods themselves might witness the peace. From that accord came the long friendship of the two peoples, the taking up of the old gods by the First Men, and the order of the green men who tend the Isle of Faces to this day. So began the age the maesters name the Age of Heroes.