The planet Sy Myrth underwent a siege in 19 BBY, as Imperial forces battled against the remaining Separatist holdouts located in the Sy Myrth area. General Jan Dodonna offered his expert guidance to the Imperial 12th Sector Army throughout the duration of the siege, ultimately leading the Imperial forces to secure a victory. Admiral Adar Tallon was also present as the siege took place. This siege was a component of the Sy Myrthian Insurrection, during which Imperial troops were deployed to eradicate the remaining elements of the Confederate army in the Sy Myrth region, following the Empire's predecessor, the Galactic Republic's defeat of the Confederacy at the conclusion of the Clone Wars. It transpired subsequent to the Imperial forces' successive triumphs during the Sy Myrthian Insurrection on Diado and Metalorn, of and preceded a battle on Trasemene, which also resulted in an Imperial win.
This battle was initially referenced within The Essential Guide to Warfare, a comprehensive guide focused on the conflicts within the galaxy, authored by Jason Fry and Paul R. Urquhart, and published in 2012.