A brief lesson in history.
Long ago in the early days of Equestria when Celestia and Luna were still just little fillies they were taught by the unicorn wizard Starswirl the Bearded. He taught them about many things including magic and science. This day however he would teach them history.
It was morning in the still young nation of Equestria, and the royal filly sisters were performing their duties. Celestia's horn glew with a golden light as she helped the sun rise up into the sky, and Luna's horn was also aglow with a blue aura as she put the moon away for the day. Watching them was Starswirl the Bearded watched patiently as he waited for them to finish. When they were done he called them into his study for a quick lesson. Luna was a little more exhausted from the job than her sister because the sages had been making her stay up at night to be sure that she grew accustomed to the task of staying up with the moon at night. He knew it was foolish to think that the moon would simply fall out of the sky without her watching it, but the council was stubborn.
"Come now my little ponies." Starswirl called for their attention.
"We're not little!" Luna defended her size, while she stood next to her sister.
"Shh." Celestia shushed her little sister, who stood only as tall as her shoulder and she herself stood not even as tall as the wizard's shoulder. "Go on Starswirl."
The little filly of the night elegantly stuck out her tongue at Celestia.
Starswirl cleared his throat and adjusted his pointed hat. "Yes well... Have you ever learned of the history of our world? From before the rule of Alicorns? From before it was called Equestria?"
The royal sisters both shook their heads. Seeing this Starswirl made a mental note to expand his lessons to them to include different subjects more often. He then continued, and his horn lit up with magic as he created simple images to go along with the lesson.
"Long ago, before magic was as widespread as it is now Equus was called Foenum. There were many different races of intelligent creatures, but of them only six had formed any kind of civilization. These six were the Alpacas, Sheep, Cattle, Reindeer, Longma, and the our ancestors the old Unicorns." His magic showed pictures of each of the six races.
"For a very long time there was peace across Foenum because the six civilizations had sealed the predators away in another realm, but after a long time the predators were coming back. So each of the six civilizations sent their bravest and most capable fighters to find the magic key that could keep the predators locked away." His magic showed pictures of the carnivorous beasts that had once preyed upon the Foenumians. "...but in their quest they fell victim to a great cataclysm that decimated the land. When the disaster was over the Longma, Alpaca, and Reindeer became extinct, and all but the Unicorns lost their place. Our ancestors saw that the world had been broken, and used their magic to change themselves and their environment so that they could make life easier for all."
"The Cattle and Sheep, as well as several other sentient races chose to give the Unicorns control in exchange for protection. For a while things were better and the Unicorns were able to develop a spell that would change them physically to allow for greater success at controlling the world. It was around this time that they separated into the three tribes, and the first Alicorns appeared. Also around this time ponies first received cutie marks. The details of exactly when each of these events occurred, and in what order is unclear." His magic showed pictures of the three pony tribes.
"And then came the war of chaos. The Draconequises invaded with their strange magic and warped the laws of physics to their content, but they were never content. Before, the Alicorns of the day and night, your mother and father, flew through the sky with the sun and moon being pulled behind them by their magic. But the amount of chaos magic that was left after the war changed the rules, and since then we Unicorn ponies have risen and set the sun and moon...with much more effort than it takes you even now." He cancelled the magic that he had been using.
"So now we ponies control most of the world while living in peace with other races, and we still give protection to the Cattle and Sheep in exchange for milk and wool. Perhaps the biggest change was in the simple beasts and animals, predators and prey both are much more tame than they were all those eons ago. Even the monsters like the hydra and chimera didn't appear until sometime between the cataclysm and the chaos war, and in fact they are found nowhere in the fossil record. ... So did you two learn anything?"
"zzzzzzzzzzzzzzzzzzzzzzzz" they both snored as they lay against each other, and Luna had taken some of Celestia's mane for a pillow.
Starswirl deadpanned as he saw the sisters had fallen asleep while he was teaching them. "Hmph." He snorted. Then he chuckled a little as he remembered that Alicorns or not they were still young, younger even than most would think because of how slowly they aged. "It is easy to forget how young, and yet how old at the same time, that you two are. I will have to make a proper schedule for teaching you rather than pulling you away from your duties at my choosing."
Starswirl shut the curtains on the window and left them to rest. As he was leaving Celestia cracked one eye open and whispered to her sister. "It worked. ...Lulu?" She nudged her sister, but the only response she got was more snoring since the smaller filly had actually fallen asleep. Celestia smiled and lay her head down next to her sister's