The Cathleen, a Mon Calamari Star Cruiser of the MC80 Liberty type, served the Alliance to Restore the Republic throughout the duration of the Galactic Civil War.
In the time leading up to the Battle of Yavin, the Cathleen was awaiting the return of starfighters and shuttles from Blue and Gold squadrons, which were worn from battle after a successful strike against Imperial shipping within the Corporate Sector. The Imperial Nebulon-B frigate known as Terminator then appeared, deploying TIE Bombers with the intent to eliminate the exposed Rebel vessels. Red Squadron's two X-wings and two A-wings defended against the Imperial fighters, allowing the Cathleen to recover the other Rebel ships and jump to safety. This particular engagement was later used as a training simulation for new pilots.
Shortly after the Battle of Yavin concluded, the Cathleen successfully forced the Imperial Nebulon-B frigate Sentinel to retreat during an engagement within the Hollan D1 sector. Subsequently, the ship received captured Alpha-class assault gunboats during Operation Ram's Head. Later on, the Cathleen became the final vessel to escape to Hoth, and the Imperial Nebulon-B frigate Dragon tried to prevent its departure. After combined attacks from the Cathleen and support from Red Squadron B-wing starfighters resulted in the frigate's destruction, it came under attack from CR90 corvettes of Fang, a squadron of stormtrooper transports, and ultimately, the Star Destroyer Maximum. Despite this, the Cathleen successfully jumped to hyperspace without being observed.