University dissertations written about Greek hero (7)
I believe the answer is:
theseus
'greek hero' is the definition.
(I've seen this before)
'university dissertations written about' is the wordplay.
'university' becomes 'u'.
'dissertations' becomes 'theses' ('thesis' can be a synonym of 'dissertation').
'written about' is an insertion indicator.
'u' going inside 'theses' is 'THESEUS'.
(Other definitions for theseus that I've seen before include "He negotiated labyrinth" , "Founder-hero of Athens" , "He slew the Minotaur" , "Athenian king" , "Rescuer of Ariadne" .)