Twin of Romulus (5)
I believe the answer is:
remus
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">twin of romulus</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for remus that I've seen before include "Uncle character in US folk stories" , "Uncle --, US narrator" , "murdered brother?" , "Brother of Romulus" , "Brother of 24 across" .)