The Treinhaus Citadel existed as a fortified structure situated on Argai Minor. Following the events of the Battle of Endor, the Galactic Empire utilized the citadel as a base of operations. In response, the New Republic deployed multiple starfighter squadrons to support ground troops in combat against the Imperial forces. The heavy fighting that ensued between the Empire and the New Republic resulted in significant destruction to the durasteel fortress, including the near total loss of the eastern wall.