Tent fire upset one ancient queen (9)
I believe the answer is:
nefertiti
'ancient queen' is the definition.
(Egyptian queen)
'tent fire upset one' is the wordplay.
'upset' is an anagram indicator.
'one' becomes 'i' (Roman numeral).
'tent'+'fire'='tentfire'
'tentfire' is an anagram of 'nefertit'.
'nefertit'+'i'='NEFERTITI'
(Other definitions for nefertiti that I've seen before include "Name of queen" , "old queen" , "Queen on the Nile" , "Oddly, the Egyptian queen is an entire fit" , "Egyptian queen, the wife of Akhenaton" .)