Messiah composer (6)
I believe the answer is:
handel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">messiah composer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for handel that I've seen before include "Water Music composer, d. 1759" , "German composer, George Frederick (1685-1759)" , "British composer of German birth, the 'father of the oratorio'" , "Old musician" , "German scorer" .)