Mon Calamari is a glimmering ocean world teaming with life and home to both the Quarren and Calamari species of sentient beings. The two peoples had warred with one another for centuries in the millennia before contact with the Old Republic before the Calamari drove the Quarren to near extinction and the peoples finally made lasting peace. In the time between then and the decline of the Republic, the Quarren and Calamari- driven by adventurous pursuit of the stars, together established an impressive network of shipyards around their home world that became widely renown for it's own local designs and later as a respected Rendili Affiliate.
Come the Rise of the Empire, Moff Tarkin sought control of the world and their mighty shipyards for the Empire to help put to use in subjugating the nearby Tion Cluster. While initially some the population benefited, in short time only the corrupt and immoral gained from an otherwise oppressive situation. Resistance to Imperial Occupation on Calamari began as worker strikes, met with an expected heavy hand. A successive series of increasingly violent exchanges resulted in wide spread resistance. When the disorganized galactic Rebellion movement gained legitimacy through public political backing of the Declaration of Rebellion, the Alliance to Restore the Republic was born and Dac would shortly become a bastion for and cornerstone to their future and very survival.
Operation Domino was a galactic wide campaign planned by Rebel High Command and implemented in the months succeeding the Delcaration of Rebellion. Various elements of their very weak central combined military would be split up to support local elements at various worlds in which large active resistance movements already existed and held potential to oust their Imperial Garrisons with surprise offensives. The projection was that these worlds would be the first of many in a domino effect of inspiring widespread uprising and revolt and initiate the rapid decline of the Empire. They'd overestimated themselves and the will to fight of their supporters and under estimated the resolve of the Empire. This was the first and only major campaign by the Rebel Alliance to seize territory outright from the Galactic Empire. Mon Calamari was the sole success of that campaign and while the surprise offensives at other worlds initially gained ground or even shrugged off their occupiers and inspired other worlds to openly declare for the Rebellion, the response was swift and devastating. As a result of the near total failure of Operation Domino, Mon Mothma refused to commit to future full scale engagement against the Empire and instead the Alliance committed to a state-less strategy of political undermining and guerilla tactics for the next five years of the Galactic Civil War.
But newly liberated from their Imperial occupiers through Operation Domino and roughly a year before the Destruction of Alderaan, as a distant glimmering beacon of hope the people of Dac working with the Alliance moved quickly to secure their position. All known routes to and from the world were heavily mined. Secret ancient and hazardous routes were used by the Alliance and Dac became a fortress of military might for the Rebellion. The Calamari and Quarren put their millennia long honed expertise in starship construction to work for the Alliance. Mon Calamari star cruisers became the face and backbone of the Rebel Fleet and their appearance in a system inspired hope in all those who cringed at their Imperial Overlords. While the Empire schemed to retake the world and teach it's people a lesson since the moment it'd been lost, the loss of many ships in the minefields and a series of logistical failures in rooting out and containing the otherwise elusive Rebellion delayed their plans. Given enough time, the story may have changed but ultimately today Dac remains the military capital of the now burgeoning New Republic, still faithfully supplying the backbone of the fleet in the form of their famed star cruisers.
