Prior to the Clone Wars by roughly ten years, a band of insurgents on the world of Halcyon seized the planet's governing body, holding them captive in an isolated area. These insurgents advocated for Halcyon's autonomy in managing its internal matters, and every attempt at dialogue with the Galactic Senate had come to naught. They controlled a fortified base on Halcyon and possessed the means to disrupt the planet's satellite navigation system and block transmissions.
The Republic dispatched a squad of Republic Judicials, under the command of a Jedi and including Wilhuff Tarkin, with orders to neutralize the insurgent faction and free the captured officials. The Republic's forces successfully subdued the Halcyon insurgents without any loss of hostage lives. The squad that included Tarkin became disoriented in the terrain en route to the insurgents' stronghold, yet managed to endure for several days before their eventual arrival (although the mission was already completed), a testament to Tarkin's ability to survive.