A true Emperor will have the capability to establish a dynasty that will last generations since to become Emperor one must be both military and politically savvy, understanding the needs of both the plebs and elite. They know what it is to seize opportunity and rise through merit alone. An Emperor can also be elected and groom their successor as opposed to inheriting the title as a product of inbreeding. This is why history may remember Kings and Queens but is is Emperors who shake the world.