Two articles about bishop of ancient city (6)
I believe the answer is:
'of ancient city' is the definition.
(relating to Thebes)
'two articles about bishop' is the wordplay.
'two articles' becomes 'thean' (article meaning part of speech: the, a etc.).
'about' indicates putting letters inside.
'bishop' becomes 'B' (chess abbreviation).
'thean' placed around 'b' is 'THEBAN'.
(Other definitions for theban that I've seen before include "Relating to an ancient Greek city" , "Old Egyptian" , "Old citizen" , "Nab the person from the ancient Greek city" , "Inhabitant of an ancient Egyptian capital" .)