"A Life For The Czar" composer (6)
I believe the answer is:
glinka
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a life for the czar composer</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 glinka that I've seen before include "Russian composer (Ruslan and Ludmilla)" , "Russian composer (A Life for the Tsar)" , "Russian composer, d. 1857" .)