Mountainous Italian island that was Napoleon Bonaparte's first place of exile (4)
I believe the answer is:
elba
(Other definitions for elba that I've seen before include "''Able was I ere I saw . . . .'' (4)" , "Abel (anag)" , "Napoleon's plaint: 'Able was I ere I saw . . . .'" , "Island in the Med" , "Napoleonic island" .)