Romulan Star Empire
From Star Trek: Theurgy Wiki
The Romulan Star Empire (or simply Romulan Empire) was a major interstellar state encompassing the Romulan people and their subject worlds and species. The Empire was known for its xenophobic character and policies of extreme secrecy, subterfuge, and territorial expansionism. By the late 23rd century, the Empire counted among the great powers in its region of the Milky Way Galaxy.
The Romulan Star Empire had borders with the United Federation of Planets, the Klingon Empire, and the Cardassian Union. The Federation-Romulan border was defined by a fixed border known as the Romulan Neutral Zone. There was also a distant Romulan border near the outer edges of the Alpha Quadrant, in a region of space where Federation starships operated on deep space missions in the 2370s.
See also: Romulan