Claim as part of historical legend (6)
I believe the answer is:
allege
'claim' is the definition.
(thesaurus)
'part of historical legend' is the wordplay.
'part of' says the answer is hidden in the clue.
'ALLEGE' can be found hidden inside 'historical legend'.
'as' acts as a link.
(Other definitions for allege that I've seen before include "Assert - maintain" , "Claim, suggest" , "Declare without actual proof" , "Make a claim without proof" , "Declare or assert without proof" .)