17th Imperial Starfleet

The 17th Starfleet was a fleet of the Imperial Navy that comprised five Imperial II-class Star Destroyers complimented by hundreds of TIE fighters. Just before the start of the Galactic Civil War, the 17th Starfleet was completely wiped out in a battle with a fleet of Clone Wars-era frigates operated by Separatists. The admiral of the fleet survived, though later defected to the Rebel Alliance as an informant.