Professor came about first ancient kingdom (7)
I believe the answer is:
macedon
'ancient kingdom' is the definition.
'macedon' can be an answer for 'kingdom' (I've seen this before). I am not certain of the 'ancient' bit.
'professor came about first' is the wordplay.
'professor' becomes 'don' (term for a university professor).
'about' indicates an anagram.
'first' is a charade indicator (letters next to each other).
'came' is an anagram of 'mace'.
'don' after 'mace' is 'MACEDON'.
Can you help me to learn more?
(Other definitions for macedon that I've seen before include "Philip's rule" , "Philip's place" , "Alexander the Great's country" , "Kingdom of Alexander the Great" .)