Long ago, magic was more raw and potent than it is today. The great civilizations of the creator races were based on endless experimentation with these energies, and during their long rules they created many new forms of life.
The cruel and decadent creator races chose to release their monstrous mistakes rather than destroy them. Most died in the jungles, yet many lived and - as thought awakened in them - they hid from their creators. When the end came at last, it was they - not the old races - who seized control of Faerûn.
And so it was that the first of the elves, the dragons, the goblin races, and an endless list of creatures of a new age took possession of their heritage. Their creators - the ancestors of the lizardfolk, bullywugs and aarakocra - declined into savage barbarism, never to rise again.
Sages speculate about the "overnight" destruction of the creator races. There are wildly diverging theories, but all agree that a rapid climate change occurred, creating a world unsuitable to them. Many believe the change resulted from a cataclysm the races unleashed upon themselves. Proponents of this theory point to the Star Mounts in the High Forest, whose origins are most likely magical and otherworldly. The elves believe that around this time the greater and lesser powers manifested themselves, aiding the new races, and confounding the survivors of the creator races. There was civilization in the North during this time period, yet little more than tantalizingly vague myths survive.