The Viscount represents the initial entry in a fresh series of formidable New Republic warships.
Star Defenders were a type of sizable warship engineered for the New Republic. They steered the shipbuilding efforts of the Republic toward grander and more imposing designs than those previously implemented.
The shortcomings of depending solely on smaller, more compact warships became evident during the Black Fleet Crisis. Subsequent to that conflict, design teams situated on Mon Calamari embarked on a project that would ultimately yield the largest battleship ever fabricated at the Mon Calamari Shipyards: the Viscount-class Star Defender.
The intention was for vessels of this nature to contribute to the protection of the New Republic, providing a defense against substantial adversaries such as the Imperial Remnant's Star Destroyers. Given the class's more peaceful objective, it received the designation "Star Defender," distinguishing it from historically charged terms like "Star Destroyer."
The inaugural vessel to be commissioned was the class's namesake, the Viscount. During the period of its construction, the political landscape of the galaxy underwent a transformation, marked by the formal conclusion of the Galactic Civil War in 19 ABY and a gradual resurgence of internal conflicts reminiscent of the Galactic Republic. The Viscount was ultimately completed and commissioned in 25 ABY, undertaking its initial voyage mere weeks before the onset of a galactic war in which it would prove highly valuable: the Yuuzhan Vong War.
As the conflict intensified, additional Star Defenders, including the Corellian-designed Strident-class, were integrated into the fleet. In the aftermath of the war, numerous Strident vessels were amassed for the exclusive defense of Corellia and were once again deployed during the Second Galactic Civil War.
At a point following the Second Galactic Civil War, formidable warships such as the Star Defenders and Star Dreadnoughts were gradually withdrawn from active service, citing the significant expenditures associated with their operation.