The Sword of the Raptor Star was a revered artifact within the Romulan Star Empire. This ancient sword was reported to have been one of those crafted by the legendary swordsmith S'harien and taken by S'task during the exile after the events of the Sundering.
In 2386, Romulan Commander Taris informed Donatra that she was going to Levaeri V in order to investigate claims that the Sword of the Raptor Star was present on that world. (ST website: The Path to 2409)
In 2409, scientists of the Romulan Republic exploring the newly-colonized Dewa III (renamed "Mol'Rihan", or "New Romulus"), discovered an ancient blade; carbon dating placed its age at roughly the time when the blade was believed to have existed, making it likely that it was indeed the fabled sword. 
- The description of the Sword matches that of the Sword of S'task; whether its a second such sword or another name for that artifact is unknown. The sword seen in STO is similar in design to the Roman Gladius of ancient Earth, but much larger.