This story is a sequel to The Fallen Age
Long ago, before the rise of Equestria, long before the Three Tribes Era even, Equus grew and prospered under the rule of the seemingly immortal Empress Cosmos. For two thousand years, she and her five Exarchs guided the many races of the world into a better future.
And then, she vanished, and her name and all she had done was forgotten.
Ten thousand years have passed since that night. Her Exarchs have not been seen in millennia, and the few who do know of that time think they died long ago.
The civilization she helped create is now forgotten by most, destroyed in a war born of xenophobia. One that heralded the rise of the Three Tribes Era.
But now signs have begun to appear. A long-forgotten prophecy is about to be fulfilled. The once and future ruler of Equus is about to be reborn. But what does this have to do with Twilight Sparkle and the five new ponies who have just arrived in Ponyville?