Before records were made, priest and choir worked together (11)
I believe the answer is:
prehistoric
'before records were made' is the definition.
'priest and choir worked together' is the wordplay.
'and' means one lot of letters go next to another.
'worked together' indicates anagramming the letters (I've seen 'working together' mean this).
'priest'+'choir'='priestchoir'
'priestchoir' with letters rearranged gives 'PREHISTORIC'.
(Other definitions for prehistoric that I've seen before include "Primeval" , "Before written records" , "Extremely old" , "very early" , "antiquated" .)