Russian rulers (5)
I believe the answer is:
tsars
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">russian rulers</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 tsars that I've seen before include "Old Russian rulers" , "Old monarchs" , "Old Russia's rulers" , "Russian emperors" .)