Finally completed and commissioned in 25 ABY, Viscount went on its maiden voyage only weeks before the start of a galactic conflict that would see it put to good use, the Yuuzhan Vong War.

During its construction, the face of galactic politics changed, with the formal end of the Galactic Civil War in 19 ABY and a gradual return to Galactic Republic-style infighting. The first vessel commissioned was the lead ship of the class, Viscount. Because of the more benign purpose of the class, the ship-type was designated 'Star Defender', to contrast the use of historically burdened terms like ' Star Destroyer'. It was envisioned that ships of this kind would help safeguard the New Republic, defend it against larger threats like the Imperial Remnant's Star Destroyers. Following the conflict, design teams at Mon Calamari went to work on a concept that would become the largest battleship ever constructed at the Mon Calamari Shipyards, the Viscount-class Star Defender. The Black Fleet Crisis pointed out the weakness of relying only on smaller, compact warships.

Defender class star destroyer