Elite timeless old city (6)

I believe the answer is:

thebes

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'old city' is the definition.
(ancient Greek city)

I don't understand the rest of the clue.

(Other definitions for thebes that I've seen before include "Classical city" , "Greek city of Oedipus" , "Greek city founded by Cadmus" , "Ancient Egyptian or Greek city" , "Ancient city, a rival to Athens" .)

I've seen this clue in The Irish Times.

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