Largest island in the Tuscan Archipelago (4)
I believe the answer is:
elba
'largest island in the tuscan archipelago' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for elba that I've seen before include "Napoleon's Mediterranean exile island" , "Napoleon's plaint: 'Able was I ere I saw . . . .'" , "''Able was I ere I saw . . . .'' (4)" , "Napoleon's prison isle" , "Island in the Med" .)