Columbus discovery of 1493 (7)
I believe the answer is:
'columbus discovery of 1493' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for antigua that I've seen before include "former British possession" , "West Indies island" , "Largest of Leeward Is." , "Aga unit in the West Indies" , "One of the Leeward Islands" .)