But what if it isn’t???? not many folks go to the trouble of burying an empty coffin.
There is an ancient Roman scroll proving it was empty.
It was written by Geraldus Riverus.
It’s also quite possible that, considering the small size, the (much) later Romans picked up some bones which they believed were those of Romulus, and built the shrine for them.
Whether they got the right bones or not, may be a matter at issue.