Princess Twilight Sparkle has always been quite the student, even before she earned the title of Princess. However, her new responsibilities require some new knowledge; an idea of what Equestria was, what the world was before Order was established and the Princesses came to power. The problem is finding somebody who can teach these things.
If only there was some ancient being who had been through everything, who had been alive before the time of Order, before Princess Luna became Nightmare Moon, before King Sombra ruled over the Crystal Empire. Perhaps someone from the Era of Chaos, when Discord Draconequus had reigned over everything... But where in Canterlot Castle would they ever find somebody like that?