-The Elements of Harmony were first created during the first Hearth's Warming, to act as guardian over Equestria
-When the advances of pony society meant that the unicorns, now artisans and craftworkers no longer had the energy and time to handle the sun and the moon, the Elements of harmony empowered a pony to act in that role: Celestia
-Over time, Celestia grew tired, and it became clear that one pony, empowered as she was, simply was not enough for the job. And so, some centuries after Celestia's empowerment, a second Alicorn was brought forth: Luna
-However, with two Alicorns now in power, struggles were inevitable. Despite being like sisters, Celestia and Luna were like the Sun and the Moon, opposed, yet related, and conflicts were inevitable, like the Nightmare Moon conflict.
-To solve this issue, it was decided that tehre was no other choice but to bring forth a third Alicorn, to serve as an Arbiter. For this role, the Elements eventually found a filly whose destiny shone bright: Twilight Sparkle.