The varied uses of a classical hero (7)
I believe the answer is:
'a classical hero' is the definition.
(I've seen this before)
'the varied uses' is the wordplay.
'varied' indicates an anagram.
'uses' with letters rearranged gives 'seus'.
'of' is the link.
(Other definitions for theseus that I've seen before include "Ancient hero" , "Shakespeare's Duke of Athens" , "Mythological hero" , "Rescuer of Ariadne" , "Greek king" .)