Leader of the Argonauts who sailed in quest of the Golden Fleece (5)
I believe the answer is:
jason
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">leader of the argonauts who sailed in quest of the golden fleece</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 jason that I've seen before include "Argonaut leader" , "Leader of the Argonauts who sailed in quest of the Golden Fleece" , "He led the Argonauts to find the Golden Fleece" , "Chief Argonaut" , "Greek hero, leader of the Argonauts" .)