Part of Attica then — some city! (6)
I believe the answer is:
athens
This clue is a double definition.
'part of attica' is the first definition.
(I know that Athens is part of Attica)
'some city' is the second definition.
(Athens is a city)
'then' acts as a link.
(Other definitions for athens that I've seen before include "Hasten to the Hellenic city" , "Hasten (anag) -- capital city" , "City in which 13 Across founded school" , "6 capital" , "Site of the Parthenon" .)