Small piece preceding Taverner's first choral work (5)
I believe the answer is:
motet
'choral work' is the definition.
(I've seen this in another clue)
'small piece preceding taverner's first' is the wordplay.
'small piece' becomes 'mote' (I can't justify this - if you can you should believe this answer much more).
'preceding' says to put letters next to each other.
'taverner's first' becomes 't' (mst letter of 'taverner').
'mote'+'t'='MOTET'
Can you help me to learn more?
(Other definitions for motet that I've seen before include "Certain one is morally superior" , "Short sacred choral piece" , "Piece for choir" , "Short sacred vocal work" , "Piece of sacred music" .)