The Thalassa was one of the few Praetor Mark IIs created, since the Empire favored Star Destroyer and dreadnought designs over battlecruisers. It was built and commissioned at some point after the end of the Clone Wars.
Decades later, the Thalassa was used by Delvardus in his warlord campaign after the Battle of Endor. At the seizure of Moorja, the battlecruiser engaged a New Republic fleet consisting of EF76 Nebulon-B escort frigates supported by Y-wing bombers. The combined force destroyed the Thalassa over Moorja. This was but one of a string of defeats suffered by Delvardus and he was soon pushed out of his conquered territory on the Rimma Trade Route.
- The Essential Guide to Warfare (First mentioned)