The Empire's takeover of Corellia was carefully orchestrated over a period of years by Sith Lord Darth Decimus and his agents. Imperial spies identified key politicians in Corellia's highest government echelons and the Empire methodically recruited these individuals by promising them lifetime power in exchange for their loyalty. Eventually, the entire Corellian Council was secretly allied with the Empire.
As the Treaty of Coruscant ended and war resumed, Corellia's government orchestrated a faked emergency that cleared the planet's hyperlanes and closed down its spaceports. The council then voted unanimously to place the world under the Imperial banner as Darth Decimus's fleet appeared in the skies above Coronet City. The invasion was over, but the war for Corellia was only beginning.