Romulus is the outer and larger moon of the main-belt asteroid 87 Sylvia.

Romulus was discovered in February 2001 from the Keck II telescope by Michael E. Brown and Jean-Luc Margot.

The moon is named after Romulus, the mythological founder of Rome, one of the twins of Rhea Silvia raised by a wolf.

87 Sylvia has a low density, which indicates that it is probably a rubble pile formed when debris from a collision between its parent body and another asteroid re-accreted gravitationally.

Therefore, it is likely that both Romulus and Remus, the second of Sylvia's moons, are smaller rubble piles which accreted in orbit around the main body from debris of the same collision.