The Belassar system, a star system situated within the Sarla sector of the Expansion Region, witnessed significant events. Before the renowned Battle of Yavin in the early stages of the Galactic Civil War, the Galactic Empire initiated actions to quell Rebel Alliance operations within this system. Subsequently, Princess Leia Organa, aboard the Alderaanian consular ship known as the Tantive IV, and accompanied by pilot Jon "Dutch" Vander, arrived to secretly aid the Rebels. The Bellasar system was part of the New Republic–controlled space from 12 ABY up to 17 ABY.
The young-readers book Star Wars Journal: Captive to Evil, penned by Jude Watson and released in 1998, marked the initial mention of the Belassar system.
The reference book The Essential Atlas, published in 2009, located the Belassar system in grid square J-8 and provided further details regarding Leia Organa's assignment there, which was initially described in Watson's narrative.