Star Wars: Plagenera
Not much is known about The Galactic Empire. It seems like it has been in power for centuries, but it is suggested in folklore it existed for only a short time before conquering earth. Likewise there are legends of a rebellion that will (or has) defeated the Empire. No signs of a galactic scale rebellion has been seen on Plagenera although some of the designs associated with rebellion do appear from time to time.
Earth’s history is like our own other than being conquered in the near future and then using the conqueror’s technology to expand to other untamed systems.
The locals had magic and dragons, but technology won out in the end. Orbital bombardment being too much for any native force to repel.