The Galactic Empire laid siege to Dalron Five after discovering its Rebel sympathies. Using techniques that had been developed by Jan Dodonna, the Empire managed to conquer the world after a devastating and lengthy siege, forcing its people to flee and live as refugees.
These refugee-camps were later on discovered by the Imperial scout Lak Sivrak, who agreed to keep their whereabouts a secret. Later on, his superiors used Sivrak's report to piece together their location and the Dalron Five refugees were finally caught.
As a result of the siege and his partial responsibility for it, Dodonna would become even more determined to aid the Alliance in its struggle to defeat the Empire.