Romulus is the name of the home planet of the powerful Romulan Empire in the Star Trek universe. There's also a neighboring planet called Remus, whose population the Romulans enslaved.
We're guessing you already figured out that Remus Lupin, Harry Potter's werewolf friend, was named after the original wolf-suckled Remus.
The asteroid Sylvia has two moons: Romulus and Remus, named after our buddies and their mom. (Source.)
Check out this chilled-out Sufjan Stevens song called "Romulus."