//------------------------------//
// The Legend 
// Story: On the Horizon 
// by mushroompone 
//------------------------------//

Once upon a time, in the ancient land of Equestria, there were two wise sisters who worked together to understand and to harness the magic upon which the land was built. The eldest sister, a powerful unicorn, learned all there was to know about magic that was good and pure; the younger, less practiced though just as mighty, sought to understand all of the dark and poisonous magic which infected the kingdom. Thus, the two sisters were able to shut out the dark magic and usher in an age of light for all the different types of ponies. But as time went on, the younger sister became resentful. The ponies of Equestria gleefully followed in the hoofsteps of the eldest sister, learning all they could about good magic, while the younger sister's contributions to magical development were shunned. 

One fateful day, the younger unicorn decided to teach a lesson to the subjects who ignored the evil potential of Equestria's magic. She unleashed a powerful dark storm upon the land, corrupting all it touched with evil intent. The elder sister tried to reason with her, but the bitterness in the young one's heart had transformed her into a wicked mare of darkness: Nightmare Moon.

She vowed that she would shroud the land in eternal night. Reluctantly, the elder sister turned to the only resource which could help her seal away the darkness: her sister's own research. Using the magical inscriptions within this mighty tome, she defeated her younger sister, and banished her permanently in the moon. The elder sister took on responsibility for magic both good and evil, educating all young unicorns in the ways of magic, and harmony has been maintained in Equestria for generations since.