The war of Cybertron wasn't just about Autobots and Decepticons, there were also civilians and rescue personnel. One such group was Rescue Bot Squadron Alpha 9, and their Wrecker bodyguard, who were charged with keeping a protoform nursery away from the fighting. To accomplish this, they hid on a planet with strange energy fields and gravitational anomalies to avoid detection. Unfortunately, the same energies caused them to crash into a mountain and remain in stasis for a thousand or so years. Eventually, the inhabitants built a city on top of that mountain, a city called Canterlot.
And now, the war is over, and the Bots are waking up.