According to commentary on the TOS season 1 Blu-ray, the idea for the Romulans came from writer Paul Schneider, who wanted worthy adversaries for Captain Kirk (William Shatner) and was inspired by the Roman Empire.
Romulans make their first appearance in the TOS season 1 episode “Balance of Terror.” We learn that after a bloody conflict with the Romulans, a peace treaty was forged between them and the Federation via subspace radio. The treaty establishes a neutral zone in which neither side’s ships are allowed to enter. A map is displayed to the Enterprise crew that shows the planets Romulus and Remus on the opposite side of the zone.
Romulus was the legendary founder of Rome. In Roman myth, Romulus and his brother Remus are born to a mortal woman, Rhea Silvia, who mates with Mars — the god of war. Left for dead by their uncle Amulius’ servants, the twins are saved by a wolf. They’re eventually raised by shepherds and, upon growing to adulthood and learning the truth about who they are, they kill their uncle and seek a place to start their own kingdom. There are different versions of how it happens, but at some point in the tale Romulus usually kills Remus in a dispute over where their new kingdom is to be founded.
Considering the treachery and violence we’ve seen the Romulans are capable of, if nothing else Schneider picked fitting names for their worlds.
Written by: Looper