Sy Myrthian Insurrection

The Sy Myrthian Insurrection was a campaign launched by the Galactic Empire in 19 BBY during the Imperial Period's Reconquest of the Rim, to drive out the holdout forces of the Confederacy of Independent Systems lead by Sy Myrthian ex-Senator Toonbuck Toora from the region around the planet Sy Myrth during the Imperial's Reconquest of the Rim following the Clone Wars. The Confederacy had been defeated by the Galactic Republic, the Empire's predecessor, at the end of the Clone Wars. During the campaign, the Imperial 12th Sector Army, under the command of General Jan Dodonna and Admiral Adar Tallon, won battles at Diado, Metalorn and besieged Sy Myrth itself before defeating the Separatist holdout forces under Toora in the Trasemene system, a battle in which Toora herself was killed, ending the Insurrection.

Prelude
The galactic conflict known as the Clone Wars ended during 19 BBY with the Galactic Republic vanquishing the Confederacy of Independent Systems. However, some Confederates continued to fight on as the Separatist holdouts at the beginning of the Imperial Period, including Sy Myrthian ex-Senator Toonbuck Toora who managed to reactivate Separatist ground and naval forces, as well as a Confederate factory world, that had been deactivated at the end of the Clone Wars in the vicinity of Toora's homeworld of Sy Myrth. Uprisings like Toora's forced the Galactic Empire, the successor of the Republic, to attempt a large campaign know as the Reconquest of the Rim. The Imperials relocated the 12th Sector Army to the world of Charros in response to Toora's uprising.

The campaign
After several months of fighting in which they reduced Toora's forces, the 12th Sector Army under the command of Admiral Adar Tallon and General Jan Dodonna were victorious at the worlds of Diado and then Metalorn. After those victories, the Imperials besieged Sy Myrth itself under Dodanna's expert guidance, eventually defeating the forces there, before Tallon and Dodanna chased down Toora's flagship Defiance's Banner with a task force led by the Praetor-class Star Battlecruiser Battalion. The endgame of the campaign came at Trasemene after the Imperial task force cornered Toora's fleet there. In the ensuing battle, the Battalion ripped apart Toora's fleet with its batteries, killing Toora and ending the Insurrection.

Aftermath
Though the Insurrection had ended, some Confederate followers continued to harass the Empire from the Kreetan Narrows region in Hutt Space, close to Sy Myrth. As a result of the activities in the Kreetan Narrows, the Empire annexed the Hutt's northern territories, which included the Narrows and the worlds of Vaathkree, Kessel, and Honoghr. Dodonna later received honors for his role in the pursuit and elimination of Toora, while he and Tallon's exploits were celebrated on the Core Worlds of the galaxy.

Behind the scenes
The insurrection was first mentioned in The Essential Guide to Warfare, an extensive guide dedicated to the conflicts in the galaxy, written by Jason Fry and Paul R. Urquhart and released in 2012.