Claudius' successor (4)
I believe the answer is:
nero
'claudius' successor' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nero that I've seen before include "Fiddling Roman emperor" , "Emperor who played the fiddle" , "Emperor said to have started the fire that destroyed Rome" , "Matricidal emperor" , "Roman emperor on the fiddle?" .)