The Ylesian Republic represented the governing body that came into being on Ylesia. This occurred after the Peace Brigade received the world from the Praetorite Vong. After the seizure of Ylesia, the Ylesian Republic possessed independence in name only. In reality, the Yuuzhan Vong wielded significant power, making it essentially a government that cooperated with the invaders. A President headed the republic, and a Senate was responsible for its governance.
Thrackan Sal-Solo received the appointment as both the initial President of the Ylesian Republic and the supreme commander of the Peace Brigade.
Ultimately, the Battle of Ylesia resulted in the defeat of both the Ylesian Republic and its associated Peace Brigade.