Roundhead leader (8)
I believe the answer is:
cromwell
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">roundhead leader</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for cromwell that I've seen before include "dictator" , "Roundhead leader" , "English general" , "His forces massacred Irish people in the 17th century" , "Thomas or Oliver?" .)