Freeholder of the old Arabian sultanate (6)
I believe the answer is:
yeoman
'freeholder' is the definition.
(yeoman is a kind of freeholder)
'the old arabian sultanate' is the wordplay.
'the old' becomes 'ye' (resembles a historical spelling of 'the').
'arabian sultanate' becomes 'Oman' (Oman is ruled by a sultan).
'ye'+'oman'='YEOMAN'
'of' acts as a link.
(Other definitions for yeoman that I've seen before include "One may (anag.)" , "Old landholder; member of The Guard" , "One guarding" , "... of the Guard (Gilbert and Sullivan)" , "Petty officer" .)