Two hundred years from now, a Republic will form. And Earth will be its center. From the hallowed halls of Earth's great temples and shrines, the Great Republic will stretch out across the whole of the Milky Way Galaxy, and things will be good. Well, as good as anything is when humans are involved. Mostly, the galaxy is humanoid, or descended from the humans that we will send to its farthest reaches. Other species will grow and develop, but all of them owe something to the Earth at the Republic's center.
For five centuries, the power of this Republic will spread and humanity will rule the stars.
Then, overnight, the government will disappear, removing itself to faraway Deklahn, a planet on the other side of the galaxy and strategically located so that no one could reach it undetected. In one night, their supporters will rise up and slaughter their opponents in a bloody coup; they will have been planning this for years. A vote will have come before the Republic Senate to remove the government from Earth; to make it stronger, more imperial. The Human Galaxy is rife with corruption and war and chaos, the bill's proponents will scream; a stronger government would end all that. But Earth will have voted it down. So they move in secret, gathering supporters from the galaxy's spies and soldiers and magnates, until they are ready. Then they will strike, and the Imperium will be born.
The new government will begin a series of conquests; horrible, bloody affairs to the farthest reaches of space that nevertheless bring much wealth and much stability to the Galaxy. The Deklahnian Senate will have voted itself vast new powers and be ruthless in pursuit of its goals. And so the government will change, and no longer be a Republic.
In response to this and the manner of their creation, Earth will rise up in rebellion. They believe they are responsible for the situation; responsible for the failures of the government. The Republic's spiritual heart, they rise to defend what they believe are the ideals of their galaxy.
They will be crushed.
Deklahn leaves them in the care of Omega, their not-so-secret police, who put the planet under martial law. Time freezes on Earth, which will see no great advances from then on out, and for five-hundred more years, they will live under the thumb of a tyrannical agency keen on destroying whatever spirit Earthlings may have possessed. To them they will send the Surgeons, their master torturers, and the Dentists, their information extractors. And they will send the worst, too: the Doctors, whose horrific experiments have will have turned them into a lesson for any child. Misbehave and the Doctors will get you...
But Earth's spirit will not be gone. It won't even be diminished. A rebellion will grow, and it will strengthen. And even if they are vastly out-armed, out-manned, and desperately alone in the universe, that will not stop them from trying.
Earth will rise once more, and they will damn well mean to win.