The Third Terran War was the final conflict between the Terran Alliance and the Imperial Remnant. The war officially begun in 20 ABY, when the rebel Terran Alliance launched a successful attack on the Super Star Destroyer, Domination, while the majority of the Imperial forces were away on Operation: Shadow Hand. The attack wiped out the major Imperial space force, though they still had two other Star Destroyers in the system, as well as killing all but three of the Imperial Sith Acolytes. The war was a short one; with the Alliance pushing the Empire off of Earth and Mars before engaging them over the star, Sol, and finally on Pluto once and for all.
After the Imperial defeat, the Alliance returned to Earth and began reconstructing Tera City, which had been destroyed in the previous war, as well as its planet, which had been heavily damaged in the three Terran Wars. While they did, however, the three surviving Sith acolytes formed a secret Sith Order, the Order of the Sith Triumvirate, to allow them to once again rule the Earth at a future date.