A vicar agog to recollect old master (10)
I believe the answer is:
caravaggio
'old master' is the definition.
(I know that Caravaggio is an old master)
'a vicar agog to recollect' is the wordplay.
'to recollect' indicates anagramming the letters.
'a'+'vicar'+'agog'='avicaragog'
'avicaragog' is an anagram of 'CARAVAGGIO'.
(Other definitions for caravaggio that I've seen before include "Italian painter known for contrasts of light/shade" , "Italian painter, d. 1610" , "Supper at Emmaus painter" , "Italian Baroque painter (d.1610)" , "Artist" .)