More than a thousand years ago, Equestria was a different place - in fact it wasn't even called Equestria! After ponykind migrated south to escape the cold and windigoes, the different tribes largely splintered on their own paths while retaining some measure of harmony; for example, the unicorns cultivated a society atop Canter Mountain, what would become Canterlot. As it was their responsibility, the unicorns continued to raise the sun and lower the moon. The task is not easy, so a special group of unicorns, simply known as the Sun Ponies and the Moon Ponies, are each charged with the responsibility. The process is strenuous, causing these ponies to go bald or mostly bald.