A Greek last seen in Sparta? (5)
I believe the answer is:
alpha
'a greek' is the definition.
(Greek equivalent to 'A')
I don't understand the rest of the clue.
(Other definitions for alpha that I've seen before include "First in order of importance (for a Greek?)" , "As heard on radio, a" , "leader in Athens, originally" , "star of utmost brilliance" , "letter opener" .)