|Commander Donatra, a Romulan female of the 24th century|
|Government:||Romulan Star Empire|
|Commander Sarsachen tr'Sauringar, a Romulan male of the 25th century|
The Romulans (Rihan: Rihannsu, "the Declared"; singular "Rihanha") were a humanoid species from the planet Romulus. They were an off-shoot of the Vulcans, their ancestors having left Vulcan in the 4th century C.E. after rejecting the teachings of Surak. The Romulan state for most of their history was known as the Romulan Star Empire, a major power in their region of the galaxy. (Star Trek)
The Romulan species was devastated in 2387 by the Hobus supernova, which destroyed many of their planets, including their adopted homeworld Romulus, and killed billions of people. (Star Trek; Star Trek Online; PIC novel: The Last Best Hope)
In the mid to late 25th century, the Romulan Star Empire and the Federation was at the height of one of their tensest time periods. Captain Courtney Covaks defied orders and crossed the Romulan Neutral Zone into Romulan territory, making it to Romulus where she made the plea before the Romulan Senate and the Praetor to call for peace between the Federation and Romulan Star Empire. Much to the surprise of the Federation council, the Romulans agreed to open talks, resulting in a lasting peace between the two organizations, and the eventual entry of the Romulans into the Federation.
One notable difference between Vulcans and Romulans was the amount of lead in their bodies. The Romulan worlds are higher in lead, which is harmless to Vulcanoids. While attempting to go undercover to investigate what was believed to be a group of renegade Vulcans, T'Noshi identified one of the group as being a Romulan spy, because she had undergone recent chelation therapy to remove the lead from her body. (Starship Tristan: Deception)