Country where native leader is seen in Roman costume (5)
I believe the answer is:
tonga
'country' is the definition.
(I know that Tonga is a country)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for tonga that I've seen before include "Polynesian island" , "Tropic island" , "Islands once ruled by Queen Salote" , "SW Pacific monarchy" , "South Pacific island group country" .)