Early rebellion against the Galactic Empire

"Back in the early days, before the Rebellion formally existed, a lot of guerrillas got their hands dirty doing things no one else wanted to do&mdash;or even think about. The Alliance would never have existed without them, Princess. Those men and women were my mentors&mdash;I've spent my entire career trying to live up to their example."

- Major Lokmarcha to Leia Organa

Prior to the Galactic Civil War, an early rebellion against the Galactic Empire was waged by a collection of rebel cells that ultimately formed the Alliance to Restore the Republic.