About 12,500 years before Robert Baratheon took the Iron Throne,

Prior to the arrival of the First Men on the continent of Westeros, the children of the forest reigned supreme throughout the land. Then, from the east the First Men arrived coming across the Arm of Dorne. As the First Men spread throughout the land and built their holdfasts, they cut down trees and burned them. This infuriated the children of the forest, who worshiped trees. They declared war on the First Men.

The two races fought a desperate war for dominance, resulting in the destruction of the Arm of Dorne and the flooding of the Neck through the magic of the greenseers of the children of the forest. Despite their obvious advantage in magic, the children were losing. The First Men were equipped with bronze swords and armor. They were bigger and stronger. Still, the wars continued.

After years of warfare, before they fought one another to a standstill, the two sides agree to a truce, signing the Pact on the Isle of Faces, agreeing to peacefully coexist and granting the open lands to humanity and the forests to the Children. In time, the First Men even adopted the gods of the children of the forest. With the signing of the Pact, the Dawn Age came to a close, The Pact lasted for four thousand years before the enigmatic Others, or White Walkers, invaded from the lands of always winter, bringing death and destruction to both races. This brings about the Age of Heroes.