One contemporary of Jesus turns up round old capital (7)

I believe the answer is:

nairobi

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'capital' is the definition.
(capital of Kenya)

I cannot understand how the remainder of the clue works.

(Other definitions for nairobi that I've seen before include "East African capital" , "Foreign capital" , "Flat round object" , "Kenyan capital" , "The capital of Kenya (7)" .)

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