Ancient mariner’s poem returned to Arab chief (4)
I believe the answer is:
emir
'chief' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for emir that I've seen before include "Top man" , "Eastern title" , "Middle-Eastern ruler" , "Leading role" , "eader abroad?" .)